43-kD Protein Research Articles

The molecular mechanisms of gap junction remodeling

c b o i m u C r p C T l t p c t m Localization of connexin43 in the heart In 1967, Revel and Karnovsky first described an aggregate f membrane associated particles that, while looking like hey blocked the extracellular space, allowed the tracer anthanum hydroxide to pass through small gaps between he aggregates and named this cluster of particles the “gap unction.” In the heart, they described these structures to be rimarily at the long ends of the cells, identified as the ntercalated disk (ID). Further studies by Page and his coleague noted the presence of a “fuzzy coat” under the gap unctions, giving rise to the speculation that the extracellular ggregates crossed the myocyte membrane and anchored ithin the cell. From these early studies grew a new field of esearch on what these aggregates were made of and how hey worked. In cardiac studies, the primary component of ardiac gap junctions was identified as a 43-kD protein, subsequently named Connexin43 (Cx43). Studies showed that unlike liver cells, where the hepatocyte connexin, connexin 32, was localized all over the cells, in the myocytes of the heart, connexins were preferentially localized to the ends of cells at the IDs such that images showing longitudinal sections of myocytes gave a straight line of staining that was evident at myocyte ends (Figure 1A). Transverse images show that Cx43 does not cover the entire ends of the myocytes; rather it is positioned in a ring around the edges of the ID (Figure 1B). This pattern has been shown in the hearts of mice, dogs, and humans, indicating that this ighly organized pattern is conserved across species. Unerstanding of the function of gap junctions as conduits for lectrical current led to hypotheses that the localization of x43 in the heart was important for the normal anisotropic onduction of the heart. Interest in the role of gap junctions in heart disease was iqued when images of diseased hearts stained for Cx43 howed that cardiac pathologies were associated with a hange in the normal pattern of Cx43 in the ventricular yocardium. Rather than being localized at the ID, Cx43 n human hearts after a myocardial infarction was found on

Characterization of role of the toxR gene in the physiology and pathogenicity of Vibrio alginolyticus

toxR, a conserved virulence-associated gene in vibrios, is identified in Vibrio alginolyticus ZJ51-O, a pathogenic strain isolated from diseased fish. To reveal the role of ToxR in the pathogenicity of V. alginolyticus, a deletion mutant was constructed by allelic exchange. The mutant showed the same level of growth in trypticase soy broth (TSB) and iron-limiting condition, as the wild type strain. However, deletion of toxR severely reduced resistance against bile salts and the capability of biofilm formation. Outer-membrane protein (OMP) analysis showed that a 37-kD protein was absent and a 43-kD protein was decreased in the mutant. By MS/MS, the two proteins are identified as the homologues of OmpT and OmpN, respectively. These data suggest that ToxR might have enhanced the bile resistance and biofilm formation through modulating the production of OMP without affecting the ability of iron acquisition and the virulence to the fish via injection. These results indicate that ToxR may assist V. alginolyticus to colonize on the surface of the fish intestine which is crucial for the initiation of the infection, though it may not be involved in the proliferation of the bacteria in the host tissue.

Tumor necrosis factor α–mediated cleavage and inactivation of SirT1 in human osteoarthritic chondrocytes

The protein deacetylase SirT1 positively regulates cartilage-specific gene expression, while the proinflammatory cytokine tumor necrosis factor α (TNFα) negatively regulates these same genes. This study was undertaken to test the hypothesis that SirT1 is adversely affected by TNFα, resulting in altered gene expression. Cartilage-specific gene expression, SirT1 activity, and results of chromatin immunoprecipitation analysis at the α2(I) collagen enhancer site were determined in RNA, protein extracts, and nuclei of human osteoarthritic chondrocytes left untreated or treated with TNFα. Protein extracts from human chondrocytes transfected with epitope-tagged SirT1 that had been left untreated or had been treated with TNFα were analyzed by immunoblotting with SirT1 and epitope-specific antibodies. The 75-kd SirT1-reactive protein present in TNFα-treated extracts was identified by mass spectroscopy, and its amino-terminal cleavage site was identified via Edman sequencing. SirT1 activity was assayed following an in vitro cathepsin B cleavage reaction. Cathepsin B small interfering RNA (siRNA) was transfected into chondrocytes left untreated or treated with TNFα. TNFα-treated chondrocytes had impaired SirT1 enzymatic activity and displayed 2 forms of the enzyme: a full-length 110-kd protein and a smaller 75-kd fragment. The 75-kd SirT1 fragment was found to lack the carboxy-terminus. Cathepsin B was identified as the TNFα-responsive protease that cleaves SirT1 at residue 533. Reducing cathepsin B levels via siRNA following TNFα exposure blocked the generation of the 75-kd SirT1 fragment. These data indicate that TNFα, a cytokine that mediates joint inflammation in arthritis, induces cathepsin B-mediated cleavage of SirT1, resulting in reduced SirT1 activity. This reduced SirT1 activity correlates with the reduced cartilage-specific gene expression evident in these TNFα-treated cells.

Duration of induced thermal tolerance and tissue-specific expression of hsp/hsc70 in the eastern oyster, Crassostrea virginica and the pacific oyster, Crassostrea gigas

We compared thermotolerance and the heat shock response of Pacific oysters ( Crassostrea gigas) and Eastern oysters ( Crassostrea virginica), both are very valuable commercial species. The former were much more resistant to high temperature, reaching maximum induced thermotolerance (IT) by 2 days after a sublethal heat shock (SHS) and lasting for at least 3 weeks, a possible record for the duration of IT in any animal. Two constitutive isoforms of 77 and 72kD, and an inducible 69kD protein were detected in both oysters, their amounts and time course after SHS varied, depending on the tissue examined. Synthesis of these three proteins in gills (ctenidia) of C. gigas was reduced to control levels within 2 days after SHS as judged by 14 C-amino acid incorporation. However, western blotting showed that the levels of these stress proteins in tissues from heat shocked C. gigas remained higher than those in controls, suggesting a reduction in protein degradation after SHS. Variable patterns of these three isoforms were detected in gills, mantle, adductor muscle and digestive gland before and after SHS. The general features described for C. gigas tissues were also observed in adductor muscle, gill and mantle of C. virginica, although some differences were also noted. We discuss the difficulties and importance associated with the use of commercially-available antibodies in the study of these stress proteins in oysters.

Hippocampal long-term depression is enhanced, depotentiation is inhibited and long-term potentiation is unaffected by the application of a selective c-Jun N-terminal kinase inhibitor to freely behaving rats

Synaptic plasticity is regarded as the major candidate mechanism for synaptic information storage and memory formation in the hippocampus. Mitogen-activated protein kinases have recently emerged as an important regulatory factor in many forms of synaptic plasticity and memory. As one of the subfamilies of mitogen-activated protein kinases, extracellular-regulated kinase is involved in the in vitro induction of long-term potentiation (LTP), whereas p38 mediates metabotropic glutamate receptor-dependent long-term depression (LTD) in vitro. Although c-Jun N-terminal kinase (JNK) has also been implicated in synaptic plasticity, the in vivo relevance of JNK activity to different forms of synaptic plasticity remains to be further explored. We investigated the effect of inhibition of JNK on different forms of synaptic plasticity in the dentate gyrus of freely behaving adult rats. Intracereboventricular application of c-Jun N-terminal protein kinase-inhibiting peptide (D-JNKI) (96 ng), a highly selective JNK inhibitor peptide, did not affect basal synaptic transmission but reduced neuronal excitability with a higher dose (192 ng). Application of D-JNKI, at a concentration that did not affect basal synaptic transmission, resulted in reduced specific phosphorylation of the JNK substrates postsynaptic density 95kD protein (PSD 95) and c-Jun, a significant enhancement of LTD and a facilitation of short-term depression into LTD. Both LTP and short-term potentiation were unaffected. An inhibition of depotentiation (recovery of LTP) occurred. These data suggest that suppression of JNK-dependent signalling may serve to enhance synaptic depression, and indirectly promote LTP through impairment of depotentiation.

Autoantibodies against 3-hydroxy-3-methylglutaryl-coenzyme A reductase in patients with statin-associated autoimmune myopathy.

In addition to inducing a self-limited myopathy, statin use is associated with an immune-mediated necrotizing myopathy (IMNM), with autoantibodies that recognize ∼200-kd and ∼100-kd autoantigens. The purpose of this study was to identify these molecules to help clarify the disease mechanism and facilitate diagnosis. The effect of statin treatment on autoantigen expression was addressed by immunoprecipitation using sera from patients. The identity of the ∼100-kd autoantigen was confirmed by immunoprecipitation of in vitro-translated 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) protein. HMGCR expression in muscle was analyzed by immunofluorescence. A cohort of myopathy patients was screened for anti-HMGCR autoantibodies by enzyme-linked immunosorbent assay and genotyped for the rs4149056 C allele, a predictor of self-limited statin myopathy. Statin exposure induced expression of the ∼200-kd/∼100-kd autoantigens in cultured cells. HMGCR was identified as the ∼100-kd autoantigen. Competition experiments demonstrated no distinct autoantibodies recognizing the ∼200-kd protein. In muscle biopsy tissues from anti-HMGCR-positive patients, HMGCR expression was up-regulated in cells expressing neural cell adhesion molecule, a marker of muscle regeneration. Anti-HMGCR autoantibodies were found in 45 of 750 patients presenting to the Johns Hopkins Myositis Center (6%). Among patients ages 50 years and older, 92.3% had taken statins. The prevalence of the rs4149056 C allele was not increased in patients with anti-HMGCR. Statins up-regulate the expression of HMGCR, the major target of autoantibodies in statin-associated IMNM. Regenerating muscle cells express high levels of HMGCR, which may sustain the immune response even after statins are discontinued. These studies demonstrate a mechanistic link between an environmental trigger and the development of sustained autoimmunity. Detection of anti-HMGCR autoantibodies may facilitate diagnosis and direct therapy.

Identification of Periplakin as a New Target for Autoreactivity in Idiopathic Pulmonary Fibrosis

Injury to alveolar epithelial cells is central to the pathophysiology of idiopathic pulmonary fibrosis (IPF). An abnormal autoimmune response directed against antigens of the alveolar epithelium may contribute to the disease. To detect circulating autoantibodies (autoAbs) directed against epithelial structures. We performed immunoblot by separating human placental amnion extract or alveolar epithelial cell (A549 cell line) proteins on polyacrylamide gels, blotting on nitrocellulose membranes, and incubating with serum from patients with IPF (n = 40) or healthy subjects (n = 40). Proteomic analysis and mass spectrometry characterized the target protein. Inhibition experiments performed with the correspondent recombinant protein confirmed our results. We identified IgG autoAbs recognizing a 200-kD protein in the serum of patients with IPF. Proteomic analysis identified this protein as human periplakin (PPL), a component of desmosomes. Anti-PPL Abs were found by immunoblot in both serum and bronchoalveolar lavage in patients with IPF: 16/40 (40%) of them were positive versus none of the control subjects. Immunohistochemistry revealed that PPL was strongly expressed in bronchial and alveolar epithelium, but that PPL exhibited changes in intracellular localization among normal and fibrotic alveolar epithelium. In an alveolar epithelial wound repair assay, an anti-PPL IgG decreased cell migration. Recombinant PPL induced bronchoalveolar lavage T lymphocyte proliferation. Patients with IPF with anti-PPL Abs had a more severe respiratory disease, despite no difference in survival. We found a new circulating autoAb directed against PPL in patients with IPF, associated with a more severe disease.

A novel autoantibody recognizing 200‐kd and 100‐kd proteins is associated with an immune‐mediated necrotizing myopathy

Myofiber necrosis without prominent inflammation is a nonspecific finding in patients with dystrophies and toxic or immune-mediated myopathies. However, the etiology of a necrotizing myopathy is often obscure, and the question of which patients would benefit from immunosuppression remains unanswered. The aim of this study was to identify novel autoantibodies in patients with necrotizing myopathy. Muscle biopsy specimens and serum samples were available for 225 patients with myopathy. Antibody specificities were determined by performing immunoprecipitations from (35)S-methionine-labeled HeLa cell lysates. Selected biopsy specimens were stained for membrane attack complex, class I major histocompatibility complex (MHC), and endothelial cell marker CD31. Muscle biopsy specimens from 38 of 225 patients showed predominantly myofiber necrosis. Twelve of these patients had a known autoantibody association with or other etiology for their myopathy. Sixteen of the remaining 26 sera immunoprecipitated 200-kd and 100-kd proteins; this specificity was observed in only 1 of 187 patients without necrotizing myopathy. Patients with the anti-200/100 autoantibody specificity had proximal weakness (100%), high creatine kinase levels (mean maximum 10,333 IU/liter), and an irritable myopathy on electromyography (88%). Sixty-three percent of these patients had been exposed to statins prior to the onset of weakness. All patients responded to immunosuppressive therapy, and many experienced a relapse of weakness when the medication was tapered. Immunohistochemical studies showed membrane attack complex on small blood vessels in 6 of 8 patients and on the surface of non-necrotic myofibers in 4 of 8 patients. Five of 8 patients had abnormal capillary morphology, and 4 of 8 patients expressed class I MHC on the surface of non-necrotic myofibers. An anti-200/100-kd specificity defines a subgroup of patients with necrotizing myopathy who previously were considered to be autoantibody negative. We propose that these patients have an immune-mediated myopathy that is frequently associated with prior statin use and should be treated with immunosuppressive therapy.

Bicarbonate‐Dependent Serine/Threonine Protein Dephosphorylation in Capacitating Boar Spermatozoa

This study investigates the dynamics of serine/threonine (S/T) protein phosphorylation in sperm incubated under capacitating (C) conditions using the boar as a model system. For the first time, this approach has identified multiple dephosphorylation events that occur in a bicarbonate-dependent fashion. Different phospho-(S/T) kinase substrate antibodies were used, and dephosphorylation of 5 S/T phosphoproteins was observed in C sperm compared with noncapacitated (N) cells. Specifically, dephosphorylation of 96-, 90-, 64-, and 55-kd proteins was detected by immunoblotting using 2 phospho-Akt substrate antibodies and a phosphoprotein kinase A substrate antibody. In addition, dephosphorylation of a 105-kd protein was detected using a phospho-ATM/ATR substrate antibody. In contrast, no dephosphorylation was observed using a phosphoprotein kinase C substrate antibody, and increased tyrosine phosphorylation of 32- and 20-kd proteins was detected in C compared with N sperm. Immunolocalization experiments revealed subtle changes in the pattern expression as well as a reduction of phosphorylation in C sperm. Whereas sperm incubated in N medium containing dibutyryl cAMP (dbcAMP) and 3-isobutyl-1-methylxanthine (IBMX) did not show protein dephosphorylation, incubation in C medium with dbcAMP/IBMX showed dephosphorylation as well as increased phosphorylation of other proteins (p68, p51, and p29). Finally, calyculin A, a phosphatase inhibitor, prevented dephosphorylation of p96, p90, p64, and p55 but not p105. Based on these data, we propose 2 pathways of protein dephosphorylation that are active during capacitation and independent of cAMP. Together, this provides direct evidence for more complex S/T phosphorylation dynamics than has been previously described for sperm undergoing capacitation.

Regulation of corneal inflammation by neutrophil-dependent cleavage of keratan sulfate proteoglycans as a model for breakdown of the chemokine gradient

Keratocan and lumican are small, leucine-rich repeat KSPGs in the extracellular matrix (ECM) of the mammalian cornea, whose primary role is to maintain corneal transparency. In the current study, we examined the role of these proteoglycans in the breakdown of the chemokine gradient and resolution of corneal inflammation. LPS was injected into the corneal stroma of C57BL/6 mice, and corneal extracts were examined by immunoblot analysis. We found reduced expression of the 52-kD keratocan protein after 6 h and conversely, increased expression of 34/37 kD immunoreactive products. Further, appearance of the 34/37-kD proteins was dependent on neutrophil infiltration to the cornea, as the appearance of these products was coincident with neutrophil infiltration, and the 34/37-kD products were not detected in explanted corneas or in CXCR2(-/-) corneas with deficient neutrophil recruitment. Furthermore, the 34/37-kD products and CXCL1/KC were detected in the anterior chamber, into which the corneal stroma drains; and CXCL1/KC was elevated significantly in keratocan(-/-) and lumican(-/-) mice. Together, these findings indicate that the inflammatory response in the cornea is regulated by proteoglycan/CXCL1 complexes, and their diffusion into the anterior chamber is consistent with release of a chemokine gradient and resolution of inflammation.

Abstract 1132: PTPRD is a frequent tumor suppressor in malignant astrocytoma

Abstract A slew of loss of heterozygosity studies for over more than a decade indicated existance of tumor suppressor/s other than p16 on 9p. With high resolution DNA microarray data, infrequent loss of a locus at 9p24 have been reported in neuroblastoma, esophageal, colon and lung cancers. Along with >30% loss of whole arm of 9p, we have observed occasional homo and heterozygous loss of a ∼2.6Mb locus, about 10Mb away from p16 gene on 9p in a few glioblastoma multiforme (GBM). Out of 14 genes located in this minimum deletion region, PTPRD expression was lost in ∼65-88% GBM (n=181) and more than 40% AA (n=48). The TCGA data showed similar frequency of loss of PTPRD expression, and mutation in ∼6% of GBM. Compared to nonneoplastic brain, the anaplastic astrocytoma (AA) and GBM had significant loss (p=0.0003 and 3.7 × 10-7, respectively) of PTPRD in our sample set; and TCGA GBM (p=2.7 × 10-14). Earlier we reported 3 genetic GBM subgroups: proneural, proliferative and mesenchymal where proneural GBM have relatively better survival than the others (Phillips et al, 2006). PTPRD expression loss were more significant in proliferative and mesenchymal GBM (P=3.7 × 10-8 and 2.6 × 10-7, respectively) than in proneural (p=0.0001) GBM, suggesting its expression level could be associated with survival. In a set of 306 TCGA GBM with survival data, PTPRD loss was associated with survival (log rank p<0.05). In a small set of GBM (n=11), PTPRD was lost at different degree and pattern in every tumor. Overexpression of PTPRD in U251 and U87 GBM cell lines with relatively little to no PTPRD expression lead to decreased growth rate (p<0.01) and survival (p<0.00001) in both the lines. PTPRD overexpression in these lines caused apoptosis (increased number of sub G0 cell population, and increased PARP cleavage). Downregulation of PTPRD in immortalized normal human astrocytes increased their growth rate and survival. Gene enrichment analysis identified 25 pathways connected to PTPRD expression level, many of them with key tyrosine kinase genes, and leads to survival or cell death phenotypes. PTPRD overexpression dephysphorylated phosphotyrosine/s of a ∼120Kd protein in U251 GBM cells. PTPRD loss has been reported to increase flank GBM xenograft growth rate (Solomon et al, 2008). PTPRD promoter hypermethylation in GBM, and loss mediated tumorigenecity in normal human astrocytes have also been reported recently (Veeriah et al, 2009). Together, this data suggest that PTPRD is a potent and frequent tumor suppressor in astrocytoma, and could be that elusive other tumor suppressor on 9p. This work was supported by the Arizona Biomedical Research Commission, Barrow Neurological Foundation, and Diane and Bruce Halle Fund. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1132.

Epidermal Growth Factor Receptor Signaling in Nonsmall Cell Lung Cancer

ABSTRACTEpidermal growth factor is a 170-kd protein that binds to a specific tyrosine kinase receptor, epidermal growth factor receptor (EGFR), on the cell surface. EGFR function is dysregulated in various malignancies including nonsmall cell lung cancer (NSCLC) leading to activation of several signal transduction pathways including K-RAS, PIK3, and STAT3 and STAT5, that promote cell cycle progression, proliferation, invasion, angiogenesis, and inhibit apoptosis. EGFR overexpression is seen in a majority of cases of NSCLC, but its prognostic role is controversial. EGFR inhibitors currently undergoing clinical trials in NSCLC include monoclonal antibodies or small molecule tyrosine kinase inhibitors. The only EGFR inhibitor currently approved for the treatment of NSCLC is erlotinib, a small molecule tyrosine kinase inhibitor. Although women, nonsmokers, patients with adenocarcinoma and patients with Asian ethnicity seem to have better outcomes with erlotinib, the factors predictive for response to these agents are currently the focus of investigation.

Utility of Fascin and JunB in Distinguishing Nodular Lymphocyte Predominant From Classical Lymphocyte-rich Hodgkin Lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and lymphocyte-rich classical Hodgkin lymphoma (LRCHL), although clinically and morphologically similar, differ biologically and in prognosis. Immunolabeling of Reed-Sternberg (RS) cells in LRCHL and lymphocytic and/or histiocytic variants (L&H cells) in NLPHL is often required to help distinguish between the 2 variants. Our aim was to evaluate fascin (a distinct 55-kd actin-bundling protein) and JunB (an activator protein-1 family transcription factor) to differentiate NLPHL from LRCHL. A total of 35 archival cases of NLPHL (n = 24) and LRCHL (n = 11) from adults and children were studied. Slides were reviewed for all cases and clinical, morphologic, and immunohistochemical features were evaluated. Each case was immunostained for fascin and JunB, and immunoreactivity of RS cells, L&H cells, and background lymphocytes were recorded. Whereas occasional L&H cells were weakly positive for fascin in 3 out of 24 (12.5%) cases of NLPHL, RS cells in LRCHL were positive for fascin in 11 out of 11 (100%) cases with a strong cytoplasmic staining pattern. JunB was positive in 10 out of 24 (41.7%) of NLPHL cases, and 11 out of 11 (100%) of LRCHL cases, showing a stippled and/or diffuse nuclear staining pattern. In addition to L & H Cells, JunB also stained small background lymphocytes, particularly in areas of progressively transformed germinal centers of NLPHL. Either stains when tested alone, if negative, or with rare L&H cell weak positivity for fascin, is indicative of NLPHL. The L&H cells of NLPHL cases were negative for concomitant staining in 24 out of 24 (100%) cases. Concomitant positive staining of classic RS cells for fascin and JunB was found in 11 out of 11 (100%) of LRCHL cases. Although fascin positivity alone supports the diagnosis of LRCHL, concomitant positivity offers stronger support and is less likely to lead to a false conclusion if aberrant fascin staining were to be encountered in a case of NLPHL. Staining for fascin and JunB provides a basis for distinguishing NLPHL from LRCHL and offers an alternative to other antibody profiles.

Identification of crab proteins that elicit IgE reactivity in snow crab–processing workers

The expanding snow crab-processing industry has resulted in increased numbers of workers at risk of occupational allergy. Our study is to identify relevant allergenic proteins in cooked snow crab meat (CM) and crab water (CW) used for cooking for improved remediation, diagnosis, and treatment. Extracts were prepared from CM extracts, CW extracts, and an air-filter collection near the crab cooker. Of the 207 workers, 24 with the highest IgE antibody reactivity to CM and CW extracts, as determined by using RASTs, were tested for reactivity to nitrocellulose membranes containing CM and CW proteins separated with SDS-PAGE. A 3-serum pool was similarly incubated against nitrocellulose-bound proteins from air samples collected near the crab cooker. Of the 207 sera tested, 27 and 39 sera exhibited positive IgE antibody reactivity (>or=2%) to CM and CW extracts, respectively. Twenty-two of 24 sera with the highest RAST activity (>or=3.5% binding) demonstrated IgE binding to multiple proteins (13.6-50 kd). A majority of the sera reacted to 4 proteins: 79% and 71% to a 34.0-kd protein, 79% and 42% to a 25-kd protein, 67% and 71% to an 18.5-kd protein, and 75% to a 14.4-kd protein in both CM and CW extracts, respectively. The pool of IgE-positive sera blotted against the air-filter extract reacted to 14.4-, 18.5-, 34.0-, 43.2-, and 50-kd proteins present in both crab extracts. Four major IgE-reactive proteins were identified in CM extracts, CW extracts, and air-filter eluate. Analysis of any potential association of protein reactivity with disease suggested crab proteins at 34.0 and 14.4 kd might be more relevant.

Thyroid Transcription Factor-1 Expression in Normal Gynecologic Tissues and its Potential Significance

Thyroid transcription factor-1 (TTF-1) is a 38-kd nuclear protein, and a member of the NKx2 family of homeodomain transcription factors. It is highly expressed in normal and neoplastic thyroid and lung tissues, and is considered a reliable marker for lung adenocarcinoma and thyroid carcinoma. Recently, expression of TTF-1 has also been reported in ovarian, endometrial, and endocervical epithelial neoplasms. Little is known about TTF-1 immunoreactivity in normal gynecologic tissues. In this study, TTF-1 expression in various non-neoplastic gynecologic tissues was investigated by standard immunohistochemistry. One hundred and eight samples of benign gynecologic tissues from adult patients who had no known history of neoplastic condition were collected. Twenty-eight endometria (12 proliferative, 11 secretory, and 5 inactive), 26 fallopian tubes, 28 cervixes (14 endocervical and 14 ectocervical), 14 myometria, and 12 ovaries were studied. In addition, 4 normal fallopian tubes and 2 ovaries from 5 pediatric patients (aged from 3 mo to 11-yr old) were evaluated. Variable TTF-1 nuclear reactivity was identified in 25 of 26 (96%) fallopian tubes (extent of positivity ranged from 2% to 60%, median 25%), 15 of 28 (54%) endometria (1% to 10%, median 5%), and 6 of 14 (43%) endocervical samples (<5%). TTF-1 was also identified in 2 of 4 (50%) pediatric fallopian tubes with 5% and 20% of the tubal epithelium being positive, respectively. No TTF-1 expression was detected in ovarian tissue (neither epithelial nor stromal tissue; neither adult nor pediatric samples), ectocervical squamous epithelium or myometrium, nor in stromal tissue in endometrium, tube, or cervix. TTF-1 reactivity was detected in both proliferative and secretory endometrium, but not in 5 inactive endometria. TTF-1 is frequently expressed in normal/non-neoplastic tubal, and less frequently in functional endometrial and endocervical epithelia, but not in ovarian surface epithelium. TTF-1 might have a functional and developmental role in normal fallopian tube and endometrium, as it is highly expressed in tubal epithelium of both adults and young children, and in functional endometrium but not in inactive endometrium. The high TTF-1 expression in tubal epithelium but not in normal ovarian surface epithelium suggests that some TTF-1-positive ovarian tumors might be related to the tubal epithelium.

Autoantibodies to a 140‐kd protein in juvenile dermatomyositis are associated with calcinosis

ObjectiveThe identification of novel autoantibodies in juvenile dermatomyositis (DM) may have etiologic and clinical implications. The aim of this study was to describe autoantibodies to a 140-kd protein in children recruited to the Juvenile DM National Registry and Repository for UK and Ireland.MethodsClinical data and sera were collected from children with juvenile myositis. Sera that recognized a 140-kd protein by immunoprecipitation were identified. The identity of the p140 autoantigen was investigated by immunoprecipitation/immunodepletion, using commercial monoclonal antibodies to NXP-2, reference anti-p140, and anti-p155/140, the other autoantibody recently described in juvenile DM. DNA samples from 100 Caucasian children with myositis were genotyped for HLA class II haplotype associations and compared with those from 864 randomly selected UK Caucasian control subjects.ResultsSera from 37 (23%) of 162 patients with juvenile myositis were positive for anti-p140 autoantibodies, which were detected exclusively in patients with juvenile DM and not in patients with juvenile DM–overlap syndrome or control subjects. No anti-p140 antibody–positive patients were positive for other recognized autoantibodies. Immunodepletion suggested that the identity of p140 was consistent with NXP-2 (the previously identified MJ autoantigen). In children with anti-p140 antibodies, the association with calcinosis was significant compared with the rest of the cohort (corrected P < 0.005, odds ratio 7.0, 95% confidence interval 3.0–16.1). The clinical features of patients with anti-p140 autoantibodies were different from those of children with anti-p155/140 autoantibodies. The presence of HLA–DRB1*08 was a possible risk factor for anti-p140 autoantibody positivity.ConclusionThis study has established that anti-p140 autoantibodies represent a major autoantibody subset in juvenile DM. This specificity may identify a further immunogenetic and clinical phenotype within the juvenile myositis spectrum that includes an association with calcinosis.

The Barley Magnesium Chelatase 150-kD Subunit Is Not an Abscisic Acid Receptor

Magnesium chelatase is the first unique enzyme of the chlorophyll biosynthetic pathway. It is composed of three gene products of which the largest is 150 kD. This protein was recently identified as an abscisic acid receptor in Arabidopsis (Arabidopsis thaliana). We have evaluated whether the barley (Hordeum vulgare) magnesium chelatase large subunit, XanF, could be a receptor for the phytohormone. The study involved analysis of recombinant magnesium chelatase protein as well as several induced chlorophyll-deficient magnesium chelatase mutants with defects identified at the gene and protein levels. Abscisic acid had no effect on magnesium chelatase activity and binding to the barley 150-kD protein could not be shown. Magnesium chelatase mutants showed a wild-type response in respect to postgermination growth and stomatal aperture. Our results question the function of the large magnesium chelatase subunit as an abscisic acid receptor.

Interaction of estrogen receptor‐α transactivation domain with nuclear proteins of mouse brain: p68 RNA helicase shows age‐ and sex‐specific change

Estrogen receptor (ER)-alpha interacts with nuclear proteins to mediate its multiple functions in the brain. However, it is not known which proteins interact with the ERalpha-transactivation domain (TAD) in mouse brain and whether they change with age and sex. Therefore, we have used affinity-purified GST-tagged mouse ERalpha-TAD fusion protein for interaction with nuclear proteins from the mouse brain. The pull-down assay and far-Western blotting detected four nuclear proteins of 100, 80, 68, and 50 kD. We have recently identified the 80-kD protein as MTA1 and demonstrated its decrease in old age. Here we report alteration in the interaction and expression of the 68-kD protein of adult and old mice of both sexes. This protein was identified as p68 RNA helicase through NCBI database search, immunoprecipitation, and immunoblotting. Further analysis showed that the extent of its interaction was relatively lower in old mice of both sexes and in male mice of both ages compared with their counterparts. However, the expression of p68 was significantly lower in old males compared with adult males, although other groups did not show significant changes. Such age- and sex-specific interaction of p68 suggests its implication in ERalpha-mediated brain functions during aging.

Identification of the arginine/ornithine antiporter ArcD from Halobacterium salinarum

This paper identifies the first arginine/ornithine antiporter ArcD from the domain of archea. The functional role of ArcD is demonstrated by transport assays with radioactive labelled arginine, by its necessity to enable arginine fermentation under anaerobic growth conditions and by the consumption of arginine from the medium during growth. All three experimentally observables are severely disturbed when the deletion strain ΔArcD is used. The isolated protein is verified by mass spectrometry and reconstituted in vesicles. The proteoliposomes are attached to a membrane and capacitive currents are recorded which appear upon initiation of the transport process by change from arginine-free to arginine-containing buffer. This clearly demonstrates that the purified 34kD protein is the functional unit.

RNAi‐mediated inhibition of MSP58 decreases tumour growth, migration and invasion in a human glioma cell line

MSP58, a 58-kD nuclear microspherule protein, is an evolutionarily conserved nuclear protein implicated in the regulation of gene transcription as well as in malignant transformation. An analysis of mRNA expression by real-time PCR revealed that MSP58 was significantly up-regulated in 29% of high-grade glioblastoma tissues as well as in four glioblastoma cell lines. In the present study, we further evaluated the biological functions of MSP58 in U251 glioma cell proliferation, migration, invasion and tumour growth in vivo by specific MSP58 knockdown using short hairpin RNA (shRNA). We found that MSP58 depletion inhibited glioma cell growth, primarily by inducing cell cycle arrest rather than apoptosis. MSP58 depletion also decreased the invasive capability of glioma cells and anchorage-independent colony formation in soft agar. Moreover, suppression of MSP58 expression significantly impaired the growth of glioma xenografts in nude mice. Finally, a cell cycle-associated gene array revealed potential molecular mechanisms contributing to cell cycle arrest in MSP58-depleted glioma cells. In summary, our data highlight the importance of MSP58 in glioma progression and provided a biological basis for MSP58 as a novel candidate target for treatment of glioma.