Cretaceous Blind Snake from Brazil Fills Major Gap in Snake Evolution

Voltage-gated potassium (K(V)) channels, such as KCNQ1 (K(V)7.1), are modulated by accessory subunits and regulated by intracellular second messengers. Accessory subunits belonging to the KCNE family exert diverse functional effects on KCNQ1, have been implicated in the pathogenesis of various genetic disorders of heart rhythm, and contribute to transducing intracellular signaling events into changes in K(V) channel activity. We investigated the interactions between calmodulin (CaM), the ubiquitous Ca(2+)-transducing protein that binds and confers Ca(2+) sensitivity to the biophysical properties of KCNQ1, and KCNE4. These studies were motivated by the observed similarities between the suppression of KCNQ1 function by pharmacological disruption of KCNQ1-CaM interactions and the effects of KCNE4 co-expression on the channel. We determined that KCNE4, but not KCNE1, can biochemically interact with CaM and that this interaction is Ca(2+)-dependent and requires a tetraleucine motif in the juxtamembrane region of the KCNE4 C terminus. Furthermore, disruption of the KCNE4-CaM interaction either by mutagenesis of the tetraleucine motif or by acute Ca(2+) chelation impairs the ability of KCNE4 to inhibit KCNQ1. Our findings have potential relevance to KCNQ1 regulation both by KCNE accessory subunits and by an important intracellular signaling molecule.

Variants in Autophagy Genes Affect Susceptibility to Both Crohn's Disease and Helicobacter pylori Infection

Transforming growth factor beta (TGF-beta) and related growth factors are essential regulators of embryogenesis and tissue homeostasis. The signaling pathways mediated by their receptors and Smad proteins are precisely modulated by various means. Xenopus BAMBI (bone morphogenic protein (BMP) and activin membrane-bound inhibitor) has been shown to function as a general negative regulator of TGF-beta/BMP/activin signaling. Here, we provide evidence that human BAMBI (hBAMBI), like its Xenopus homolog, inhibits TGF-beta- and BMP-mediated transcriptional responses as well as TGF-beta-induced R-Smad phosphorylation and cell growth arrest, whereas knockdown of endogenous BAMBI enhances the TGF-beta-induced reporter expression. Mechanistically, in addition to interfering with the complex formation between the type I and type II receptors, hBAMBI cooperates with Smad7 to inhibit TGF-beta signaling. hBAMBI forms a ternary complex with Smad7 and the TGF-beta type I receptor ALK5/TbetaRI and inhibits the interaction between ALK5/TbetaRI and Smad3, thus impairing Smad3 activation. These findings provide a novel insight to understand the molecular mechanism underlying the inhibitory effect of BAMBI on TGF-beta signaling.

Common Musculoskeletal Disorders in Women

Targeting DNA With Fingers and TALENs.

Although the microtubule (MT) cytoskeleton has been shown to facilitate nuclear import of specific cancer-regulatory proteins including p53, retinoblastoma protein, and parathyroid hormone-related protein (PTHrP), the MT association sequences (MTASs) responsible and the nature of the interplay between MT-dependent and conventional importin (IMP)-dependent nuclear translocation are unknown. Here we used site-directed mutagenesis, live cell imaging, and direct IMP and MT binding assays to map the MTAS of PTHrP for the first time, finding that it is within a short modular region (residues 82-108) that overlaps with the IMPβ1-recognized nuclear localization signal (residues 66-108) of PTHrP. Importantly, fluorescence recovery after photobleaching experiments indicated that disruption of the MT network or mutation of the MTAS of PTHrP decreases the rate of nuclear import by 2-fold. Moreover, MTAS functions depend on mutual exclusivity of binding of PTHrP to MTs and IMPβ1 such that, following MT-dependent trafficking toward the nucleus, perinuclear PTHrP can be displaced from MTs by IMPβ1 prior to import into the nucleus. This is the first molecular definition of an MTAS that facilitates protein nuclear import as well as the first delineation of the mechanism whereby cargo is transferred directly from the cytoskeleton to the cellular nuclear import apparatus. The results have broad significance with respect to fundamental processes regulating cell physiology/transformation.

Assessment of Antibody Protection against Malaria Sporozoites Must Be Done by Mosquito Injection of Sporozoites

The human snRNA genes transcribed by RNA polymerase II (pol II) and III (pol III) have different core promoter elements. Both gene types contain similar proximal sequence elements (PSEs) but differ in the absence (pol II) or presence (pol III) of a TATA-box, which, together with the PSE, determines the assembly of a pol III-specific pre-initiation complex. BRFU is a factor exclusively required for transcription of the pol III-type snRNA genes. We report that recruitment of BRFU to the TATA-box of these promoters is TATA-binding protein (TBP)-dependent. BRFU in turn stabilizes TBP on TATA-containing template and extends the TBP footprint both upstream and downstream of the TATA element. The core domain of TBP is sufficient for BRFU.TBP.DNA complex formation and for interaction with BRFU off the template. We have mapped amino acid residues within TBP and domains of BRFU that mediate this interaction. BRFU has no specificity for sequences flanking the TATA-box and also forms a stable complex on the TATA-box of the pol II-specific adenovirus major late promoter (AdMLP). Furthermore, pol III-type transcription can initiate from an snRNA gene promoter containing an AdMLP TATA-box and flanking sequences. Therefore, the polymerase recruitment is not simply determined by the sequence of the TATA-box and immediate flanking sequences.

Human Cytomegalovirus and Kidney Transplantation: A Clinician's Update

Germline stem cells: toward the regeneration of spermatogenesis

Pneumococcal Bacteremia: Lessons Learned, Yet More to Learn

For many decades, cell-free nucleic acids have been known to be present in peripheral blood. Several studies have identified tumor-specific and/or tumor-associated alterations in the circulating nucleic acids of patients with various cancers. In recent years, cell-free microRNA (miRNA) have been stably detected in the plasma and serum, like other molecules; their presence in the blood has attracted the attention of researchers due to their potential use as valuable blood biomarkers.1Schwarzenbach H. Hoon D.S. Pantel K. Cell-free nucleic acids as biomarkers in cancer patients.Nat Rev Cancer. 2011; 11: 426-437Crossref PubMed Scopus (2199) Google Scholar MiRNAs are short, noncoding RNAs that play important roles in various physiologic and developmental processes. The mature miRNAs are produced from long primary transcripts through 2 sequential cleavage steps. The long primary miRNA transcript is cleaved by the Drosha complex in the nucleus, generating intermediate precursor miRNA. Precursor miRNA is transported by exportin-5 from the nucleus into the cytoplasm, and then subjected to further cleavage by a Dicer RNAase III enzyme, generating a short double-strand miRNA. One strand (guided strand) of mature miRNA is then incorporated into the RNA-induced silencing complex and subsequently hybridize to the 3′-untranslated region of their target mRNAs to repress translation or degrade these mRNAs. Thus, a single miRNA can influence the expression of hundreds of genes and allow them to function in a coordinated manner. Therefore, miRNAs have been implicated as key molecules in all cellular processes. Numerous studies have shown that alterations in miRNA expression correlate with various diseases, including the development and progression of cancer, and some miRNAs can function as oncogenes or tumor suppressors. These findings have opened up a new and interesting field in the diagnosis of cancer and the treatments of cancer patients. Mitchell et al2Mitchell P.S. Parkin R.K. Kroh E.M. et al.Circulating microRNAs as stable blood-based markers for cancer detection.Proc Natl Acad Sci U S A. 2008; 105: 10513-10518Crossref PubMed Scopus (6792) Google Scholar first demonstrated that circulating miRNAs had the potential to be new biomarkers in patients with solid cancers. In recent years, several papers have demonstrated that circulating miRNAs can also be detected in the peripheral blood of patients with digestive tract cancers. Although the origins and physiologic functions of cell-free miRNAs in the blood remain to be fully elucidated, a noninvasive assay for miRNAs should be developed to exploit these molecules as potential diagnostic and prognostic biomarkers. This assay undoubtedly contributes to an improvement in the clinical outcomes of cancer patients. In this article, we review the current state of biological and clinical research regarding circulating miRNAs of digestive tract cancer patients and discuss the future perspectives. It has been theorized that the necrosis and the apoptosis of tumor cells are the main sources of cell-free nucleic acids in the plasma and serum. However, several recent studies have demonstrated that extracellular nucleic acids, especially miRNAs, occur not only through cell lysis but also through active secretion.1Schwarzenbach H. Hoon D.S. Pantel K. Cell-free nucleic acids as biomarkers in cancer patients.Nat Rev Cancer. 2011; 11: 426-437Crossref PubMed Scopus (2199) Google Scholar, 3Valadi H. Ekström K. Bossios A. et al.Exosome-mediated transfer of mRNAs and microRNAs is a novel mechanism of genetic exchange between cells.Nat Cell Biol. 2007; 9: 654-659Crossref PubMed Scopus (9739) Google Scholar, 4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar, 5Pigati L. Yaddanapudi S.C. Iyengar R. et al.Selective release of microRNA species from normal and malignant mammary epithelial cells.PLoS One. 2010; 5: e13515Crossref PubMed Scopus (497) Google Scholar Cell-derived endogenous miRNAs are present in the blood in a remarkably stable form that is protected from endogenous RNase activity. In contrast, synthetic exogenous miRNAs are rapidly degraded when added directly to the plasma.2Mitchell P.S. Parkin R.K. Kroh E.M. et al.Circulating microRNAs as stable blood-based markers for cancer detection.Proc Natl Acad Sci U S A. 2008; 105: 10513-10518Crossref PubMed Scopus (6792) Google Scholar Kosaka et al4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar clearly demonstrated that a subset of miRNAs was packaged into exosome vesicles and released through a ceramide-dependent secretory mechanism. Arroyo et al6Arroyo J.D. Chevillet J.R. Kroh E.M. et al.Argonaute2 complexes carry a population of circulating microRNAs independent of vesicles in human plasma.Proc Natl Acad Sci U S A. 2011; 108: 5003-5008Crossref PubMed Scopus (2672) Google Scholar systematically investigated circulating miRNAs in the plasma and serum using differential centrifugation and size-exclusion chromatography techniques. This group demonstrated ≥2 populations of circulating miRNAs in the plasma and serum and discovered agonaute-2, a key effector protein involved in miRNA-mediated silencing as an miRNA carrier in the blood.6Arroyo J.D. Chevillet J.R. Kroh E.M. et al.Argonaute2 complexes carry a population of circulating microRNAs independent of vesicles in human plasma.Proc Natl Acad Sci U S A. 2011; 108: 5003-5008Crossref PubMed Scopus (2672) Google Scholar In addition, high-density lipoprotein has been described as an alternative transporter of extracellular miRNAs in human plasma.7Vickers K.C. Palmisano B.T. Shoucri B.M. et al.MicroRNAs are transported in plasma and delivered to recipient cells by high-density lipoproteins.Nat Cell Biol. 2011; 13: 423-433Crossref PubMed Scopus (2256) Google Scholar All circulating miRNAs, regardless of whether they are incorporated into protein complexes and/or cell-derived microvesicles, seem to be adequately protected against the degradation caused by the abundant RNases in human plasma and serum. Indeed, the extracellular miRNAs in the plasma and serum are extremely stable under severe conditions, such as extended storage and exposure to multiple freeze–thaw cycles.2Mitchell P.S. Parkin R.K. Kroh E.M. et al.Circulating microRNAs as stable blood-based markers for cancer detection.Proc Natl Acad Sci U S A. 2008; 105: 10513-10518Crossref PubMed Scopus (6792) Google Scholar Regarding the composition of circulating miRNAs, Pigati et al5Pigati L. Yaddanapudi S.C. Iyengar R. et al.Selective release of microRNA species from normal and malignant mammary epithelial cells.PLoS One. 2010; 5: e13515Crossref PubMed Scopus (497) Google Scholar investigated the difference between extracellular and cellular miRNAs using epithelial cell lines and concluded that the release of miRNAs did not necessarily reflect the abundance of miRNAs in the cell of origin. Kosaka et al4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar also demonstrated that some specific miRNAs were expressed to a greater extent in cell-derived exosomes compared with their donor cells.4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar Moreover, other groups demonstrated that the non–vesicle-associated miRNA profiles within protein complexes were distinctly different from the purified, exosomes-associated miRNA profiles.6Arroyo J.D. Chevillet J.R. Kroh E.M. et al.Argonaute2 complexes carry a population of circulating microRNAs independent of vesicles in human plasma.Proc Natl Acad Sci U S A. 2011; 108: 5003-5008Crossref PubMed Scopus (2672) Google Scholar These findings indicate that intracellular miRNAs are exported to the extracellular environment through a selective secretion mechanism. Interestingly, recent studies have demonstrated that extracellular miRNAs not only circulate in stable forms, but can also be incorporated into other surrounding and distant recipient cells in which they fulfill distinctive functions.8Skog J. Würdinger T. van Rijn S. et al.Glioblastoma microvesicles transport RNA and proteins that promote tumour growth and provide diagnostic biomarkers.Nat Cell Biol. 2008; 10: 1470-1476Crossref PubMed Scopus (3954) Google Scholar, 9Rechavi O. Erlich Y. Amram H. et al.Cell contact–dependent acquisition of cellular and viral nonautonomously encoded small RNAs.Genes Dev. 2009; 23: 1971-1979Crossref PubMed Scopus (100) Google Scholar, 10Zernecke A. Bidzhekov K. Noels H. et al.Delivery of microRNA-126 by apoptotic bodies induces CXCL12-dependent vascular protection.Sci Signal. 2009; 2: ra81Crossref PubMed Scopus (1130) Google Scholar, 11Kosaka N. Iguchi H. Ochiya T. Circulating microRNA in body fluid: a new potential biomarker for cancer diagnosis and prognosis.Cancer Sci. 2010; 101: 2087-2092Crossref PubMed Scopus (1144) Google Scholar, 12Pegtel D.M. Cosmopoulos K. Thorley–Lawson D.A. et al.Functional delivery of viral miRNAs via exosomes.Proc Natl Acad Sci U S A. 2010; 107: 6328-6333Crossref PubMed Scopus (1309) Google Scholar, 13Kosaka N. Iguchi H. Yoshioka Y. et al.Competitive Interactions of Cancer Cells and Normal Cells via Secretory MicroRNAs.J Biol Chem. 2012; 287: 1397-1405Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar Rechavi et al9Rechavi O. Erlich Y. Amram H. et al.Cell contact–dependent acquisition of cellular and viral nonautonomously encoded small RNAs.Genes Dev. 2009; 23: 1971-1979Crossref PubMed Scopus (100) Google Scholar demonstrated that functional signals spread across cell boundaries between immune cells in a contact-dependent manner. Pegtel et al12Pegtel D.M. Cosmopoulos K. Thorley–Lawson D.A. et al.Functional delivery of viral miRNAs via exosomes.Proc Natl Acad Sci U S A. 2010; 107: 6328-6333Crossref PubMed Scopus (1309) Google Scholar reported that Epstein–Barr virus miRNAs were secreted from infected B cells and were present in both the circulation and noninfected non-B cells. This group also demonstrated that miRNAs were transferred from infected to noninfected cells in vivo and were functional (upon transfer via exosomes) in primary monocyte-derived dendritic cells. Other groups have shown that miR-126 in apoptotic bodies derived from atherosclerotic endothelial cells induces the CXCL-12–dependent vascular protection process in recipient vascular cells.10Zernecke A. Bidzhekov K. Noels H. et al.Delivery of microRNA-126 by apoptotic bodies induces CXCL12-dependent vascular protection.Sci Signal. 2009; 2: ra81Crossref PubMed Scopus (1130) Google Scholar There have also been some reports regarding miRNA-mediated intercellular communication in a neoplastic environment. Skog et al8Skog J. Würdinger T. van Rijn S. et al.Glioblastoma microvesicles transport RNA and proteins that promote tumour growth and provide diagnostic biomarkers.Nat Cell Biol. 2008; 10: 1470-1476Crossref PubMed Scopus (3954) Google Scholar reported that microvesicles that housed miRNAs derived from glioblastomas were taken up by and fulfilled functions in human brain microvascular endothelial cells in culture. Kosaka et al4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar also demonstrated that miR-146a, which is a tumor-suppressive miRNA in prostate cancer, significantly knocked down the target ROCK1 protein expression and decreased cell proliferation in a recipient prostate cancer cell line.4Kosaka N. Iguchi H. Yoshioka Y. et al.Secretory mechanisms and intercellular transfer of microRNAs in living cells.J Biol Chem. 2010; 285: 17442-17452Abstract Full Text Full Text PDF PubMed Scopus (1591) Google Scholar Their subsequent paper demonstrated that a variety of tumor-suppressive miRNAs were secreted by a normal adult prostatic epithelial cell line, and among these secretory miRNAs, miR-143 could inhibit growth exclusively in cancer cells both in vitro and in vivo.13Kosaka N. Iguchi H. Yoshioka Y. et al.Competitive Interactions of Cancer Cells and Normal Cells via Secretory MicroRNAs.J Biol Chem. 2012; 287: 1397-1405Abstract Full Text Full Text PDF PubMed Scopus (235) Google Scholar Other groups found that the let-7 miRNA family was abundant in the extracellular fractions derived from a metastatic gastric cancer (GC) cell line, but not those derived from a low metastatic parental cell line, and it has been speculated that some cancer cells maintain their oncogenesis via specific extracellular miRNAs.14Ohshima K. Inoue K. Fujiwara A. et al.Let-7 microRNA family is selectively secreted into the extracellular environment via exosomes in a metastatic gastric cancer cell line.PLoS One. 2010; 5: e13247Crossref PubMed Scopus (515) Google Scholar On the other hand, exosomes released from neoplastic cells have been reported to suppress immune surveillance, and cell-free miRNAs contained within the exosomes may be responsible for the immunosuppression systems.15Zhang H.G. Grizzle W.E. Exosomes and cancer: a newly described pathway of immune suppression.Clin Cancer Res. 2011; 17: 959-964Crossref PubMed Scopus (233) Google Scholar These findings support the presence of miRNA-mediated intercellular communication in the normal cellular environment and the tumor environment (Figure 1) . Several methods can be used for extracting miRNAs; however, efficient protocols with high reproducibility should be utilized for the extraction of circulating miRNAs owing to the small amounts present in the plasma and serum. Commercial extraction kits that utilize glass fiber filters in the purification process have been widely used for clinical blood samples, and there are several methods for quantification. A polymerase chain reaction (PCR)-based technique using a stem-loop reverse-transcriptase (RT) primer has been widely used for determining quantity. A microarray assay, which can analyze hundreds of miRNAs simultaneously, has also been utilized for the identification of a specific marker among many circulating miRNAs. Recent advances in technology allow for the use of an oligonucleotide array to quantify the amount of circulating miRNAs without the need for PCR. Most recently, researchers have identified circulating miRNAs as new diagnostic markers in patients with cancer using direct sequencing methods16Brase J.C. Wuttig D. Kuner R. et al.Serum microRNAs as non–invasive biomarkers for cancer.Mol Cancer. 2010; 9: 306Crossref PubMed Scopus (366) Google Scholar (Table 117Zhang C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google Scholar, 18Komatsu S. Ichikawa D. Takeshita H. et al.Circulating microRNAs in plasma of patients with oesophageal squamous cell carcinoma.Br J Cancer. 2011; 105: 104-111Crossref PubMed Scopus (233) Google Scholar, 19Tsujiura M. Ichikawa D. Komatsu S. et al.Circulating microRNAs in plasma of patients with gastric cancers.Br J Cancer. 2010; 102: 1174-1179Crossref PubMed Scopus (578) Google Scholar, 20Liu R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google Scholar, 21Liu H. Zhu L. Liu B. et al.Genome-wide microRNA profiles identify miR-–378 as a serum biomarker for early detection of gastric cancer.Cancer Lett. 2012; 316: 196-203Crossref PubMed Scopus (234) Google Scholar, 22Konishi H. Ichikawa D. Komatsu S. et al.Detection of gastric cancer–associated microRNAs on microRNA microarray comparing pre- and post-operative plasma.Br J Cancer. 2012; 106: 740-747Crossref PubMed Scopus (165) Google Scholar, 23Ng E.K. Chong W.W. Jin H. et al.Differential expression of microRNAs in plasma of patients with colorectal cancer: a potential marker for colorectal cancer screening.Gut. 2009; 58: 1375-1381Crossref PubMed Scopus (1055) Google Scholar, 24Huang Z. Huang D. Ni S. et al.Plasma microRNAs are promising novel biomarkers for early detection of colorectal cancer.Int J Cancer. 2010; 127: 118-126Crossref PubMed Scopus (868) Google Scholar, 25Wang L.G. Gu J. Serum is a promising novel marker for early detection of colorectal 2012; PubMed Scopus Google Scholar, H. Zhang L. et al.Circulating plasma is a novel biomarker for metastatic cancer and One. 2011; PubMed Scopus Google Scholar, Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google Scholar, Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Scholar, Zhang K. H. et al.Circulating microRNAs as biomarkers for 2011; PubMed Scopus Google Scholar, Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google Scholar, J. C. X. et al.Circulating and in patients with or 2011; PubMed Scopus Google Scholar, J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Scholar, Y. H. H. et al.Circulating as a novel biomarker for 2012; 56: Full Text Full Text PDF PubMed Scopus Google Scholar, J. Y. X. et al.Serum microRNA as a potential marker for Sci. 2011; PubMed Scopus Google Scholar, J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google Scholar, A. N. et and and in with circulating and Res. 2010; PubMed Scopus Google Scholar, Huang X. H. et al.Circulating as a novel marker in 2010; PubMed Scopus Google Scholar, S. K. Chen et expressed miRNAs in the plasma may provide a signature for J Res. 2010; Google Scholar, N. A. et and serum microRNAs in the and in patients with One. 2011; PubMed Scopus Google Scholar, R. Komatsu S. Ichikawa D. et diagnostic of circulating in plasma of patients with J Cancer. 2011; 105: PubMed Scopus Google Scholar, J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google miRNAs in cell or other C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google S. Ichikawa D. Takeshita H. et al.Circulating microRNAs in plasma of patients with oesophageal squamous cell carcinoma.Br J Cancer. 2011; 105: 104-111Crossref PubMed Scopus (233) Google M. Ichikawa D. Komatsu S. et al.Circulating microRNAs in plasma of patients with gastric cancers.Br J Cancer. 2010; 102: 1174-1179Crossref PubMed Scopus (578) Google or other R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google in the H. Zhu L. Liu B. et al.Genome-wide microRNA profiles identify miR-–378 as a serum biomarker for early detection of gastric cancer.Cancer Lett. 2012; 316: 196-203Crossref PubMed Scopus (234) Google H. Ichikawa D. Komatsu S. et al.Detection of gastric cancer–associated microRNAs on microRNA microarray comparing pre- and post-operative plasma.Br J Cancer. 2012; 106: 740-747Crossref PubMed Scopus (165) Google E.K. Chong W.W. Jin H. et al.Differential expression of microRNAs in plasma of patients with colorectal cancer: a potential marker for colorectal cancer screening.Gut. 2009; 58: 1375-1381Crossref PubMed Scopus (1055) Google Z. Huang D. Ni S. et al.Plasma microRNAs are promising novel biomarkers for early detection of colorectal cancer.Int J Cancer. 2010; 127: 118-126Crossref PubMed Scopus (868) Google in the L.G. Gu J. Serum is a promising novel marker for early detection of colorectal 2012; PubMed Scopus Google cancer H. Zhang L. et al.Circulating plasma is a novel biomarker for metastatic cancer and One. 2011; PubMed Scopus Google in the Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google in the Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Zhang K. H. et al.Circulating microRNAs as biomarkers for 2011; PubMed Scopus Google Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google not for J. C. X. et al.Circulating and in patients with or 2011; PubMed Scopus Google in the J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Y. H. H. et al.Circulating as a novel biomarker for 2012; 56: Full Text Full Text PDF PubMed Scopus Google J. Y. X. et al.Serum microRNA as a potential marker for Sci. 2011; PubMed Scopus Google in the J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google A. N. et and and in with circulating and Res. 2010; PubMed Scopus Google in the Huang X. H. et al.Circulating as a novel marker in 2010; PubMed Scopus Google S. K. Chen et expressed miRNAs in the plasma may provide a signature for J Res. 2010; Google N. A. et and serum microRNAs in the and in patients with One. 2011; PubMed Scopus Google R. Komatsu S. Ichikawa D. et diagnostic of circulating in plasma of patients with J Cancer. 2011; 105: PubMed Scopus Google in the J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google microRNA colorectal direct esophageal gastric polymerase chain in the in a new microRNA colorectal direct esophageal gastric polymerase chain Zhang et C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google Scholar have investigated the serum miRNA profiles of patients with esophageal squamous cell using miRNAs using direct this group identified serum miRNAs and as biomarkers. The under the for the miRNAs were for serum tumor and patients in the early of the could be from using the miRNA C. Wang C. Chen X. et al.Expression profile of microRNAs in serum: a fingerprint for esophageal squamous cell carcinoma.Clin Chem. 2010; 56: 1871-1879Crossref PubMed Scopus (289) Google Scholar plasma from group also the plasma expression of miRNAs that were to be with the development of on found that the plasma of to be in patients in the and the were significantly in compared with A of the in plasma was the of an in serum tumor which that circulating miRNAs may be for diagnosis of in S. Ichikawa D. Takeshita H. et al.Circulating microRNAs in plasma of patients with oesophageal squamous cell carcinoma.Br J Cancer. 2011; 105: 104-111Crossref PubMed Scopus (233) Google Scholar However, there have been reports regarding circulating miRNAs for the other group first reported the of circulating miRNAs as biomarkers in patients with miRNAs and which have been reported to be in as miRNAs and their in plasma using In the plasma of these miRNAs the tumor miRNA and were significantly in patients in the also found that the plasma of these miRNAs were significantly in compared with M. Ichikawa D. Komatsu S. et al.Circulating microRNAs in plasma of patients with gastric cancers.Br J Cancer. 2010; 102: 1174-1179Crossref PubMed Scopus (578) Google Scholar Liu et R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google Scholar have investigated the serum miRNA profiles of patients with using miRNAs using direct this group identified serum miRNAs and as biomarkers for found that the expression of serum miRNAs was with the tumor and the for the miRNAs were for serum tumor R. Zhang C. Hu Z. et al.A five-microRNA signature identified from genome–wide serum microRNA expression profiling serves as a fingerprint for gastric cancer diagnosis.Eur J Cancer. 2011; 47: 784-791Abstract Full Text Full Text PDF PubMed Scopus (392) Google Scholar Other groups have investigated serum miRNA profiles using miRNA and concluded that was the biomarker for detection in the serum, with and the expression in primary was compared with normal H. Zhu L. Liu B. et al.Genome-wide microRNA profiles identify miR-–378 as a serum biomarker for early detection of gastric cancer.Cancer Lett. 2012; 316: 196-203Crossref PubMed Scopus (234) Google Scholar The selective release of specific cellular miRNAs from the tumor cells or from normal as could these et E.K. Chong W.W. Jin H. et al.Differential expression of microRNAs in plasma of patients with colorectal cancer: a potential marker for colorectal cancer screening.Gut. 2009; 58: 1375-1381Crossref PubMed Scopus (1055) Google Scholar first reported that circulating miRNAs could be potential noninvasive markers for colorectal cancer patients. This group plasma from patients using a miRNA microarray and found that and were in the plasma of patients and in compared with they demonstrated that the detection of could from other and The was with and an E.K. Chong W.W. Jin H. et al.Differential expression of microRNAs in plasma of patients with colorectal cancer: a potential marker for colorectal cancer screening.Gut. 2009; 58: 1375-1381Crossref PubMed Scopus (1055) Google this has been by other Huang et Z. Huang D. Ni S. et al.Plasma microRNAs are promising novel biomarkers for early detection of colorectal cancer.Int J Cancer. 2010; 127: 118-126Crossref PubMed Scopus (868) Google Scholar the plasma of miRNAs that were to be in in This group found that and had a diagnostic for and and that patients with could be from the using these 2 Z. Huang D. Ni S. et al.Plasma microRNAs are promising novel biomarkers for early detection of colorectal cancer.Int J Cancer. 2010; 127: 118-126Crossref PubMed Scopus (868) Google Scholar Wang et L.G. Gu J. Serum is a promising novel marker for early detection of colorectal 2012; PubMed Scopus Google Scholar the serum expression of miRNAs and in and metastatic patients and reported that serum had the potential to be a noninvasive biomarker for the early detection of in L.G. Gu J. Serum is a promising novel marker for early detection of colorectal 2012; PubMed Scopus Google Scholar et Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google Scholar reported the first of the direct of circulating miRNAs from the plasma without RNA extraction and found that the direct of plasma could be used as a potential noninvasive diagnostic and prognostic biomarker for Huang et al.Circulating directly from plasma is a potential diagnostic and prognostic marker of colorectal cancer and is with 2010; PubMed Scopus Google Scholar et Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Scholar first reported the of circulating miRNAs as biomarker for cancer identified as an miRNA of by miRNA profiles in the process of development using of serum was found in the of of patients and the were significantly Y. Kosaka N. M. et as a potential diagnostic marker for 2009; PubMed Scopus Google Scholar et Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google Scholar investigated the serum of miRNAs and to identify new but only the was significantly in the serum of patients compared with or viral B patients without and the of were also significantly in serum Wang H. et al.Serum as for in with B One. 2011; PubMed Scopus Google Scholar et J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Scholar investigated plasma miRNAs using an miRNA microarray in a of patients. This group first on the of the microarray and subsequently identified miRNAs and using for the miRNA reported that their miRNA could patients from B patients and patients and it is a promising marker for the early diagnosis of J. L. X. Hu J. et al.Plasma to 2011; PubMed Scopus Google Scholar Wang et J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google Scholar the plasma of miRNAs and that have been implicated in cancer development in The plasma of miRNA were in patients compared with the The for miRNA were not but they to when the miRNAs were J. Chen J. et al.MicroRNAs in plasma of patients as novel blood-based biomarkers of Res. 2009; 2: PubMed Scopus Google Scholar et A. N. et and and in with circulating and Res. 2010; PubMed Scopus Google Scholar identified 2 of the family and that were in using This group also found that these 2 miRNAs were significantly in the of and patients compared with of and et N. A. et and serum microRNAs in the and in patients with One. 2011; PubMed Scopus Google Scholar identified serum miRNAs and as diagnostic biomarkers of in an circulating miRNAs and demonstrated that the circulating miRNAs could as not only diagnostic markers but also of the Liu et J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google Scholar miRNA and in the plasma of and patients using All miRNA were significantly in patients compared with patients and This group concluded that the of and the marker was among various in from and J. J. Y. et of plasma microRNAs with serum for early detection of cancer.Int J Cancer. 2011; Scopus Google Scholar Circulating miRNAs are for use as valuable biomarkers owing to their in the and of Therefore, circulating miRNAs may be used for the clinical in cancer and early or and for the the small of which is a that miRNAs from other for an of using and direct

IscA is a key member of the iron-sulfur cluster assembly machinery found in bacteria and eukaryotes. Previously, IscA was characterized as an alternative iron-sulfur cluster assembly scaffold, as purified IscA can host transient iron-sulfur clusters. However, recent studies indicated that IscA is an iron-binding protein that can provide iron for the iron-sulfur cluster assembly in a proposed scaffold IscU (Ding H., Clark, R. J., and Ding, B. (2004) J. Biol. Chem. 279, 37499-37504). To further elucidate the roles of IscA in the biogenesis of iron-sulfur clusters, we reevaluate the iron binding activity of IscA under physiologically relevant conditions. The results indicate that in the presence of the thioredoxin reductase system, Escherichia coli IscA binds iron with an iron association constant of 2.0 x 10(19) M(-1) in vitro. Whereas all three components (thioredoxin 1, thioredoxin reductase and NADPH) in the thioredoxin reductase system are essential for mediating the iron binding in IscA, only catalytic amounts of thioredoxin 1 and thioredoxin reductase are required. In contrast, IscU fails to bind iron in the presence of the thioredoxin reductase system, suggesting that the iron binding in IscA is specific. Nevertheless, the thioredoxin reductase system can promote the iron-sulfur cluster assembly in IscU in the presence of the iron-loaded IscA, cysteine desulfurase (IscS), and L-cysteine, demonstrating a physiologically relevant system for the biogenesis of iron-sulfur clusters. The results provide additional evidence for the hypothesis that IscA is capable of recruiting intracellular "free" iron and delivering the iron for the iron-sulfur cluster assembly in IscU.

Invasion of host cells by apicomplexan parasites, including Plasmodium falciparum and Toxoplasma gondii, is a multistep process. Central to invasion is the formation of a tight junction, an aperture in the host cell through which the parasite pulls itself before settling into a newly formed parasitophorous vacuole. Two protein groups, derived from different secretory organelles, the micronemal protein AMA1 and the rhoptry proteins RON2, RON4, and RON5, have been shown to form part of this structure, with antibodies targeting P. falciparum AMA1 known to inhibit invasion, probably via disruption of its association with the PfRON proteins. Inhibitory AMA1-binding peptides have also been described that block P. falciparum merozoite invasion of the erythrocyte. One of these, R1, blocks invasion some time after initial attachment to the erythrocyte and reorientation of the merozoite to its apical pole. Here we show that the R1 peptide binds the PfAMA1 hydrophobic trough and demonstrate that binding to this region prevents its interaction with the PfRON complex. We show that this defined association between PfAMA1 and the PfRON complex occurs after reorientation and engagement of the actomyosin motor and argue that it precedes rhoptry release. We propose that the formation of the AMA1-RON complex is essential for secretion of the rhoptry contents, which then allows the establishment of parasite infection within the parasitophorous vacuole.

Factor XIII (FXIII) is a pro-transglutaminase found in the plasma as well as intracellularly in platelets and macrophages. Plasma FXIII is activated by thrombin cleavage (FXIIIa*) and acts in the final stages of blood coagulation cascade. In contrast, the function and activation of cellular FXIII are less characterized. Cellular FXIII relies on a conformational activation of the protein. The nonproteolytic activation of FXIII to FXIIIa° induced by Ca(2+) alone is well known, but up until now it has been discussed under which conditions the process can be induced and whether it can be reversed. Here, we study the nature of the Ca(2+)-induced FXIII activation. Previously used methods to evaluate FXIII activity detect both FXIIIa* and FXIIIa° because they rely on occurrence of enzyme activity or on active site Cys-314 solvent accessibility. Therefore, an analytical HPLC method was developed that separates zymogen recombinant FXIII (rFXIII) from rFXIIIa°. The data demonstrate that nonproteolytic activation and deactivation are highly dependent on Ca(2+) concentration, buffer, and salt components. Moreover, it is established that Ca(2+) activation of rFXIII is fully reversible, and only 2-5 mm CaCl(2) is sufficient to retain full rFXIIIa° activity. However, below 2 mm CaCl(2) the rFXIIIa° molecule deactivates. The deactivated molecule can subsequently undergo a new activation round. Furthermore, it is demonstrated that thermal stress of freeze-dried rFXIII can induce a new predisposed form that activates faster than nonstressed rFXIII.