Subgroup Of Family Research Articles

CXCL5 regulation of proliferation and migration in human non-small cell lung cancer cells.

Epithelial neutrophil-activating peptide-78 (CXCL5), a member of the subgroup of CXC-type chemokine family, is an inflammatory factor involved in the progression of lung cancer, but the underlying mechanism remains unclear. In this study, we investigated the effects of CXCL5 on proliferation and migration in non-small cell lung cancer (NSCLC) using tissue microarrays from NSCLC patients and H460 cells transfected with a CXCL5-interfered lentivirus vector or stimulated with recombinant CXCL5. We observed that the expression of CXCL5 was significantly higher in lung cancer cell lines, and high CXCL5 was associated with high chemokine (C-X-C motif) receptor 2 expression and was significantly associated with poor differentiation. The high expression of CXCL5 was associated with poor NSCLC prognosis and was an independent predictive factor. Furthermore, downregulation of CXCL5 in H460 cells significantly reduced proliferation and migration. Recombinant CXCL5 promoted H460 cell proliferation and movement by activating MAPK/ERK1/2 and PI3K/AKT signaling. Our study elucidates the important role of CXCL5 in the progression and prognosis of NSCLC. These findings suggested that CXCL5 might be a potential biomarker and novel therapeutic target for lung cancer.

Functional Analysis of a Putative Type III Secretion System in Stress Adaption by Mesorhizobium alhagi CCNWXJ12-2T.

Mesorhizobium alhagi CCNWXJ12-2T, isolated from root nodules of the desert plant Alhagi sparsifolia, contains two type III secretion systems (T3SSs). T3SSs are specialized machinery with wide distribution in bacteria that inject effector proteins into target cells. Our previous study showed that the expression of M. alhagi T3SS1 is upregulated in high-salt conditions. Here, phylogenetic analysis of T3SS1 using the core protein RhcU suggested that T3SS1 belongs to the α-Rhc II subgroup of the Rhc T3SS family. To elaborate the function of M. alhagi CCNWXJ12-2T T3SS1 in stress adaption, two T3SS1 mutants (ΔrhcQ and ΔMA29250) were constructed and analyzed. β-galactosidase transcriptional fusion assays showed that activity of the promoter of T3SS1 was induced by salts. Mutant ΔrhcQ was more sensitive to NaCl and LiCl than the wild-type, but ΔMA29250 was not. Both mutants were more sensitive to KCl than the wild-type. The intracellular Na+ concentration in ΔrhcQ in high-NaCl conditions (0.4 M) increased by 37% compared to that of the wild-type strain, while the Na+ concentration in ΔMA29250 increased by 13%. The K+ concentration in both mutants increased by 16% compared to the wild-type in high-KCl conditions (0.3 M). Strain ΔrhcQ showed decreased survival compared to the wild-type after treatment with H2O2, while the survival rate of ΔMA29250 was almost the same as that of the wild-type. Antioxidant enzyme activities in ΔrhcQ were lower than those in the wild-type strain, but this was not the case for ΔMA29250. Our data elucidate the beneficial effects of T3SS1 in the adaption of M. alhagi CCNWXJ12-2T to stress.

Evaluation of PUMA and NOXA expression as predictive biomarkers in prostate cancer.

28 Background: PUMA and NOXA are two pro-apoptotic members of the BH3-only subgroup of the BCL-2 family. These two proteins play a role in the initiation of apoptosis. The objective of this study is to analyse their expression by immunofluorescence, alone or in combination, in benign and tumor prostate tissues to determine if there is a correlation between their expression and patient biochemical recurrence (BCR). Methods: Biomarker antibodies were verified for specificity and optimized by western blot and with tissue microarrays (TMA) containing prostate cancer cell lines and cell line derived xenograft tissues. Subsequently, quantification of expression for both biomarkers was performed on six TMA generated from radical prostatectomy samples (285 patients). The TMA were constructed using two cores of benign adjacent to the tumor and two cores of tumor tissue from each patient. Analysis of biomarker expression was semi-automated using the VisiomorphDP software. To optimize the analysis, we developed 2 different immunofluorescence masks: a cocktail of anti-cytokeratin-8 and -18 antibodies to identify epithelial cells and a combination of anti-p63 and anti-cytokeratin high marker weight to discriminate benign glands within tumor cores. Correlation with patient clinical outcome was determined with SPSS V20 software. Results: There was no correlation of PUMA and NOXA expression and BCR in tumor cores and stroma. In contrast, in benign epithelial cells Kaplan-Meier analysis showed a significant association between an extreme (low or high) PUMA expression and BCR (Log rank = 11.349, p = 0.001). Further analysis revealed a significant association between high NOXA expression in benign epithelial cells and BCR (Log rank = 6.133, p = 0.013). The combination of extreme PUMA and high NOXA identified patients with a poor prognosis (Log rank = 16.041, p = 0.000). In a multivariate Cox regression model, PUMA and NOXA proteins were also identified as independent predictive biomarkers of BCR. Conclusions: By studying benign epithelial cells adjacent to the tumor we identified two potential biomarkers that discriminate high-risk patients, independent of Gleason score or pathologic stage.

The impact of family ownership on capital structure of firms: Exploring the role of zero-leverage, size, location and the global financial crisis

In this article, we investigate the influence of family ownership on firm leverage across different subgroups of family and non-family firms. In addition, we examine the influence of firm size, geographical location and the 2008 global financial crisis on the capital structure of family firms. In both cases, we study the probability of firms using debt and, conditional on its use, the proportion of debt issued. We find that family ownership affects both decisions positively, namely, when the firm is large or located in a metropolitan area. For small firms located outside metropolitan areas, there is no clear family ownership effect. We also find the 2008 crisis had a substantial, but diversified, impact on family firm leverage. On the one hand, all family firms were more prone to use debt after 2008; on the other, the proportion of debt held by levered family firms decreased for micro and small firms, but increased for large firms. Overall, the crisis effects on family firm leverage seem to be the result of both supply- and demand-side factors, with the former particularly affecting the availability of debt to micro and small firms.

Sequential structural and antiferromagnetic transitions in BaFe2Se3 under pressure

The discovery of superconductivity in the two-leg ladder compound BaFe$_2$S$_3$ has established the 123-type iron chalcogenides as a novel and interesting subgroup of the iron-based superconductors family. However, in this 123 series, BaFe$_2$Se$_3$ is an exceptional member, with a magnetic order and crystalline structure different from all others. Recently, an exciting experiment reported the emergence of superconductivity in BaFe$_2$Se$_3$ at high pressure [J.-J. Ying, et al., Phys. Rev. B 95, 241109 (R) (2017)]. In this publication, we report a first principles study of BaFe$_2$Se$_3$. Our analysis unveils a variety of qualitative differences between BaFe$_2$S$_3$ and BaFe$_2$Se$_3$, including in the latter an unexpected chain of transitions with increasing pressure. First, by gradually reducing the tilting angle of iron ladders, the crystalline structure smoothly transforms from Pnma to Cmcm at ~6 GPa. Second, the system becomes metallic at 10.4 GPa. Third, its unique ambient pressure Block antiferromagnetic ground state is replaced by the more common CX antiferromagnetic order at ~12 GPa, the same magnetic state of the 123-S ladder. This transition is found at a pressure very similar to the experimental superconducting transition. Finally, all magnetic moments vanish at 30 GPa. This reported theoretical diagram of the complete phase evolution is important because of the technical challenges to capture many physical properties in high-pressure experiments. The information obtained in our calculations suggest different characteristics for superconductivity in BaFe$_2$Se$_3$ and BaFe$_2$S$_3$: in 123-S pairing occurs when magnetic moments vanish, while in 123-Se the transition region from Block- to CX-type magnetism appears to catalyze superconductivity. Finally, an additional superconducting dome above ~30 GPa is expected to occur.

Characterization of the [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough.

The [NiFeSe] hydrogenases are a subgroup of the well-characterized family of [NiFe] hydrogenases, in which a selenocysteine is a ligand to the nickel atom in the binuclear NiFe active site instead of cysteine. These enzymes display very interesting catalytic properties for biological hydrogen production and bioelectrochemical applications: high H2 production activity, bias for H2 evolution, low H2 inhibition, and some degree of O2 tolerance. Here we describe the methodologies employed to study the [NiFeSe] hydrogenase isolated from the sulfate-reducing bacteria D. vulgaris Hildenborough and the creation of a homologous expression system for production of variant forms of the enzyme.

Numerals in Lokono-Wayuunaiki: Reconstruction and implications for internal classification

Abstract The goal of this paper is to contribute to the understanding of the diachronic development of the Lokono-Wayuunaiki subgroup of the Arawak language family by focusing on a structured set of lexemes of recurrent interest for historical linguists. In this paper, I reconstruct the cardinal numerals from ‘one’ to ‘four’ in Proto-Lokono-Wayuunaiki (PLW). For each reconstructed etymon, I will discuss how regular sound change and attested morphological patterns support the reconstructed forms and the implied diachronic developments in the two daughter languages, Lokono and Wayuunaiki. On the basis of these reconstructions, I argue that the form for ‘three’ and the construction involved in the derivation of the form for ‘four’ constitute innovations shared only by Lokono and Wayuunaiki among Arawak languages, thus supporting the recognition of Lokono-Wayuunaiki as a legitimate subgroup of the Arawak family.

Sorghum Dw2 Encodes a Protein Kinase Regulator of Stem Internode Length

Sorghum is an important C4 grass crop grown for grain, forage, sugar, and bioenergy production. While tall, late flowering landraces are commonly grown in Africa, short early flowering varieties were selected in US grain sorghum breeding programs to reduce lodging and to facilitate machine harvesting. Four loci have been identified that affect stem length (Dw1-Dw4). Subsequent research showed that Dw3 encodes an ABCB1 auxin transporter and Dw1 encodes a highly conserved protein involved in the regulation of cell proliferation. In this study, Dw2 was identified by fine-mapping and further confirmed by sequencing the Dw2 alleles in Dwarf Yellow Milo and Double Dwarf Yellow Milo, the progenitor genotypes where the recessive allele of dw2 originated. The Dw2 locus was determined to correspond to Sobic.006G067700, a gene that encodes a protein kinase that is homologous to KIPK, a member of the AGCVIII subgroup of the AGC protein kinase family in Arabidopsis.

Complete sequence and comparative genomic analysis of eight native Pseudomonas syringae plasmids belonging to the pPT23A family

BackgroundThe pPT23A family of plasmids appears to be indigenous to the plant pathogen Pseudomonas syringae and these plasmids are widely distributed and widely transferred among pathovars of P. syringae and related species. pPT23A-family plasmids (PFPs) are sources of accessory genes for their hosts that can include genes important for virulence and epiphytic colonization of plant leaf surfaces. The occurrence of repeated sequences including duplicated insertion sequences on PFPs has made obtaining closed plasmid genome sequences difficult. Therefore, our objective was to obtain complete genome sequences from PFPs from divergent P. syringae pathovars and also from strains of P. syringae pv. syringae isolated from different hosts.ResultsThe eight plasmids sequenced ranged in length from 61.6 to 73.8 kb and encoded from 65 to 83 annotated orfs. Virulence genes including type III secretion system effectors were encoded on two plasmids, and one of these, pPt0893-29 from P. syringae pv. tabaci, encoded a wide variety of putative virulence determinants. The PFPs from P. syringae pv. syringae mostly encoded genes of importance to ecological fitness including the rulAB determinant conferring tolerance to ultraviolet radiation. Heavy metal resistance genes encoding resistance to copper and arsenic were also present in a few plasmids. The discovery of part of the chromosomal genomic island GI6 from P. syringae pv. syringae B728a in two PFPs from two P. syringae pv. syringae hosts is further evidence of past intergenetic transfers between plasmid and chromosomal DNA. Phylogenetic analyses also revealed new subgroups of the pPT23A plasmid family and confirmed that plasmid phylogeny is incongruent with P. syringae pathovar or host of isolation. In addition, conserved genes among seven sequenced plasmids within the same phylogenetic group were limited to plasmid-specific functions including maintenance and transfer functions.ConclusionsOur sequence analysis further revealed that PFPs from P. syringae encode suites of accessory genes that are selected at species (universal distribution), pathovar (interpathovar distribution), and population levels (intrapathovar distribution). The conservation of type IV secretion systems encoding conjugation functions also presumably contributes to the distribution of these plasmids within P. syringae populations.

Co-amplification of phosphoinositide 3-kinase enhancer A and cyclin-dependent kinase 4 triggers glioblastoma progression.

Glioblastoma (GBM) is the most common primary brain tumor and has a dismal prognosis. Amplification of chromosome 12q13–q15 [Cyclin-dependent kinase 4 (CDK4) amplicon] is frequently observed in numerous human cancers including GBM. Phosphoinositide 3-kinase enhancer (PIKE) is a group of GTP-binding proteins that belong to the subgroup of centaurin GTPase family, encoded by CENTG1 located in CDK4 amplicon. However, the pathological significance of CDK4 amplicon in GBM formation remains incompletely understood. In the current study, we show that co-expression of PIKE-A and CDK4 in TP53/PTEN double knockout GBM mouse model additively shortens the latency of glioma onset and survival compared to overexpression of these genes alone. Consequently, p-mTOR, p-Akt and p-ERK pathways are highly upregulated in the brain tumors, in alignment with their oncogenic activities by CDK4 and PIKE-A stably transfected in GBM cell lines. Hence, our findings support that PIKE amplification or overexpression coordinately acts with CDK4 to drive GBM tumorigenesis.

Evolution of the 3R-MYB Gene Family in Plants.

Plant 3R-MYB transcription factors are an important subgroup of the MYB super family in plants; however, their evolutionary history and functions remain poorly understood. We identified 225 3R-MYB proteins from 65 plant species, including algae and all major lineages of land plants. Two segmental duplication events preceding the common ancestor of angiosperms have given rise to three subgroups of the 3R-MYB proteins. Five conserved introns in the domain region of the 3R-MYB genes were identified, which arose through a step-wise pattern of intron gain during plant evolution. Alternative splicing (AS) analysis of selected species revealed that transcripts from more than 60% of 3R-MYB genes undergo AS. AS could regulate transcriptional activity for some of the plant 3R-MYBs by generating different regulatory motifs. The 3R-MYB genes of all subgroups appear to be enriched for Mitosis-Specific Activator element core sequences within their upstream promoter region, which suggests a functional involvement in cell cycle. Notably, expression of 3R-MYB genes from different species exhibits differential regulation under various abiotic stresses. These data suggest that the plant 3R-MYBs function in both cell cycle regulation and abiotic stress response, which may contribute to the adaptation of plants to a sessile lifestyle.

Pollination of Orchid Flowers: Quantitative and Domain-Specific Analysis of Ethylene Biosynthetic and Hormone-Induced Gene Expression

Pollination initiates a suite of postpollination developmental events in orchid flowers. Ethylene plays a key role in coordinating these developmental changes. We examined the temporal-spatial patterns of expression of genes encoding 1-aminocyclopropane 1-carboxylate acid (ACC) synthase and ACC oxidase following pollination and associated hormonal treatments using quantitative procedures. We present the first in situ hybridization analysis of ACC synthase and an earlier time course of ACC oxidase gene expression. In immature ovaries, critical morphological changes involving cell differentiation and growth were affected by pollination and various hormone and inhibitor treatments. Patterns of ACC synthase and ACC oxidase mRNA accumulation were determined by RNA blot hybridization analysis. Gene expression analysis using real-time quantitative polymerase chain reaction indicated that the unpollinated ovary had very low levels of ACC oxidase expression at 6 h and that pollination caused near-maximal levels in this organ by 12 h. Quantitative mRNA analysis showed that auxin could mimic pollination by inducing a similar pattern of organ-specific expression, but earlier and to higher levels. Ethylene had the most dramatic effect by inducing gene activity to its highest levels at all time points and in all floral organs. The early induction in situ hybridization analyses contribute new findings that ACC synthase and ACC oxidase transcripts were localized sequentially in epidermal, phloem, and parenchyma cells of the stigma and that by 8–12 h postpollination, saturation had occurred throughout the stigma. Finally, phylogenetic analysis of orchid ACC synthase proteins leads to the conclusion that at least a subgroup of the angiosperm ACC synthase gene family is induced by auxin but may not be posttranscriptionally regulated, indicating regulatory sequence but not functional divergence of orchid genes with other seed plant ACC synthase proteins.

Investigation of the regulation mechanism of Arabidopsis thaliana anion channel SLAH2

In recent years a slow-type anion channel (SLAC) family composing five members, including slow anion channel associated 1 (SLAC1) and four SLAC1 homologs (SLAHs), has been identified in Arabidopsis thaliana. The anion channels are activated by calcium-dependent protein kinases (CPKs) and play crucial roles in mediating anion fluxes across plasma membranes. SLAH2 is specifically expressed in root stele cells and has been characterized as a nitrate-selective anion channel activated by CPK21 and CBL-interacting protein kinase 23 (CIPK23). However, the interaction between CPKs and SLAH2 and how it is regulated remains to be elucidated. In this study we found that SLAH2 could be activated by a few CPKs from three subgroups of the CPK family. Out of those CPKs, the constitutively active form of CPK2 from subgroup 1 activates SLAH2, whereas the native as well as constitutively active form of CPK3 from subgroup 2 and CPK7, CPK10, and CPK32 from subgroup 3 activate SLAH2. We also explored the role of SLAH2 in root-to-shoot nitrate transport by measuring the nitrate contents in xylem sap, but no significant differences were observed between the slah2-1 T-DNA insertion mutant and SLAH2 overexpression lines. Together, these data demonstrate that SLAH2 is regulated by multiple CPKs with variable Ca2+ sensitivities. Further research is required to understand the role of SLAH2 in nitrate transport.

Autoantibodies to NR2A Peptide of the Glutamate/NMDA Receptor in Patients with Seizure Disorders in Neuropsychiatric Systemic Lupus Erythematosus.

Objective. Seizure disorders are one of the most disabling, life-threatening, and the least understood syndromes associated with neuropsychiatric SLE (NPSLE). N-Methyl-D-aspartate (NMDA) receptors are a subgroup of the glutamate receptor family, whose NR2A subunit was found on neuronal cells (anti-NR2A) in NPSLE patients with different types of epilepsy. The present study was conducted to determine the serum levels of anti-NR2A antibodies in a large group of SLE patients, to investigate the possible correlation between the presence of the NR2A specific antibodies and NPSLE-related seizure disorders. Methods and Results. The study population consisted of 107 SLE patients and 43 age- and sex-matched healthy controls. 73 SLE patients had active disease. 36 of these had NPSLE. NMDA levels were measured by ELISA. Clinical and serological parameters were assessed according to routine procedures. The levels of anti-NR2A antibodies were significantly higher in NPSLE patients, compared with non-NPSLE patients and healthy controls. Furthermore, the levels of NPSLE in patients with seizure disorders were shown to be higher than in those with cognitive dysfunction and other CNS symptoms, however, without significance. Increase in serum anti-NR2A antibodies levels correlated to anti-dsDNA antibody and SLEDAI as well as complement levels. Conclusion. We suggest that anti-NR2A antibodies play a role in the pathogenesis of NPSLE with seizure disorders.

A novel Gossypium barbadense ERF transcription factor, GbERFb, regulation host response and resistance to Verticillium dahliae in tobacco.

Ethylene-responsive factors (ERFs) are commonly considered to play animportant role in pathogen defense responses. However, only few of ERF members have been characterized in Sea island cotton (Gossypium barbadense). Here, we reported a novel AP2/ERF transcription factors gene, named GbERFb which was cloned and identified from Sea island cotton by RACE. The expression of GbERFb was significantly induced by treatments with ethylene, Methyl jasmonate, salicylic acid, wounding, H2O2 and Verticillium dahliae (V. dahliae) infection. Bioinformatics analysis showed that GbERFb protein containing a conserved ERF DNA binding domain and a nuclear localization signal sequence, belonged to IXb subgroup of the ERF family. Further experiments demonstrated that GbERFb could bind the GCC box cis-acting element and interact with GbMAPKb (MAP kinase) directly in yeast. Over-expression of GbERFb in tobacco could increase the disease resistance to V. dahliae. The results suggest that the GbERFb, a new AP2/ERF transcription factor, could enhance the resistance to V. dahliae and be useful in improvement of crop resistance to pathogenes.

Discovery and structural characterisation of new fold type IV-transaminases exemplify the diversity of this enzyme fold.

Transaminases are useful biocatalysts for the production of amino acids and chiral amines as intermediates for a broad range of drugs and fine chemicals. Here, we describe the discovery and characterisation of new transaminases from microorganisms which were enriched in selective media containing (R)-amines as sole nitrogen source. While most of the candidate proteins were clearly assigned to known subgroups of the fold IV family of PLP-dependent enzymes by sequence analysis and characterisation of their substrate specificity, some of them did not fit to any of these groups. The structure of one of these enzymes from Curtobacterium pusillum, which can convert d-amino acids and various (R)-amines with high enantioselectivity, was solved at a resolution of 2.4 Å. It shows significant differences especially in the active site compared to other transaminases of the fold IV family and thus indicates the existence of a new subgroup within this family. Although the discovered transaminases were not able to convert ketones in a reasonable time frame, overall, the enrichment-based approach was successful, as we identified two amine transaminases, which convert (R)-amines with high enantioselectivity, and can be used for a kinetic resolution of 1-phenylethylamine and analogues to obtain the (S)-amines with e.e.s >99%.

Targeting and alteration of tight junctions by bacteria and their virulence factors such as Clostridium perfringens enterotoxin.

The integrity of tight junctions, which regulate paracellular permeability, is challenged by many bacterial pathogens. This is caused by inflammatory responses triggered by pathogens and direct interaction of bacteria or their toxins with host epithelial cells. In some cases, tight junction proteins represent receptors for cell surface proteins or toxins of the pathogen, such as Clostridium perfringens enterotoxin (CPE). CPE causes diarrhea and cramps-the symptoms of a common foodborne illness, caused by C. perfringens type A. It uses a subgroup of the claudin family of tight junction proteins as receptors and forms pores in the membrane of intestinal epithelial cells. Ca2+ influx through these pores finally triggers cell damage. In this review, we summarize tight junction targeting and alteration by a multitude of different microorganisms such as C. perfringens, Escherichia coli, Helicobacter pylori, Salmonella typhimurium, Shigella flexneri, Vibrio cholerae, Yersinia enterocolitica, protozoan parasites, and their proteins. A focus is drawn towards CPE, the interaction with its receptors, cellular, and pathophysiological consequences for the intestinal epithelium. In addition, we portend to the use of CPE-based claudin modulators for drug delivery as well as diagnosis and therapy of cancer.

Automatic Spontaneous Speech Recognition for Punjabi Language Interview Speech Corpus

Automatic Speech Recognition presents natural phenomena for the communication among man and machine. The purpose of Speech Recognition speech system is to convert the sequence of sound units in the form of text description. The main objective of the research work is to develop the automatic spontaneous speech model for the Punjabi language. Punjabi is categorized as a constituent of the Indo-Aryan subgroup of the Indo-European family of languages. So far no work has been done in the field of spontaneous Punjabi speech recognition system. In spontaneous speech system, the sounds are usually unprompted and non- designed and are commonly described by repetitions, repairs, false start, partial words and non-planned words, silence gap etc. In this paper, the focus is on the development of the spontaneous speech model for the recognition of the Punjabi language. The GUI for Punjabi speech model also has been created and tested for the live Punjabi interview speech corpus. The recognition accuracy is 98.6% for Punjabi sentences and 98.8% for Punjabi words. The sphinx toolkit and java programming are used to build a spontaneous speech model for Punjabi live speech.

The Transcriptional Changes of trim Genes Associated with Parkinson's Disease on a Model of Human Induced Pluripotent Stem Cells.

Over the last few years, in vitro models, based on patient-derived induced pluripotent stem cells (iPSCs), have received considerable attention for modeling different neurodegenerative disorders. Using this model, we analyzed transcription of 15 tripartite motif (trim) genes in iPSCs, derived from the different groups: Parkinson's disease (PD) patients bearing mutations in different genes, patient with the sporadic form of PD, and the healthy individuals. The transcription was observed during neuronal differentiation of the cells in vitro into neuronal stem cells and terminally differentiated neurons. The transcription of over 50% of these genes, belonging to different sub-groups of the TRIM family, varied between PD patients and healthy individuals during the reprogramming of fibroblasts into iPSCs and the following neuronal differentiation. Moreover, the transcription of the trim6 and trim24 genes was different between cells, derived from PD patients, and control cells at all stages. The transcription of the four trim genes (trim5α, 26, 27, 31) remained unchanged during almost all investigated stages, compared with the controls. We suppose that the revealed changes in the transcription of several trim genes reflect their possible role in neurodegenerative processes at the early stages of PD. These genes may act as a gear unit between the PD progression and the deregulation of the immune system.

Immunolocalization of the TASK2 Potassium Channel in Frog Kidney.

TASK2 (K2P5. 1, KCNK5) is a two-pore domain K⁺ channel belonging to the TALK subgroup of the K2P family of proteins. TASK2 expression has been reported in a variety of cells and tissues ranging from kidney to immune cells and including specific neurons, its proposed functions spanning from involvement in the regulation of cell volume to control of excitability. The purpose of this study was to determine the tubule location ofthe TASK2 K⁺ channel protein in frog kidney applying polyclonal antibody against the carboxyl terminus of human TASK2 (KCNK5) protein. Immunohistochemical analysis revealed that TASK2 is expressed on distal tubules and proximal epithelial cells. TASK2 is strongly expressed predominantly on the luminal part ofthe proximal epithelial cells and slightly cytoplasmatic staining is expressed. Distal tubules showed diffuse cytoplasmatic staining as well as slight staining on the apical parts ofthe cells. These findings suggest that the TASK2 K⁺ channel has cell-specific roles in renal potassium ion transport.