Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the epididymis and vas deferens, the vacuolar H(+)ATPase (V-ATPase), located in the apical pole of narrow and clear cells, is required to establish an acidic luminal pH. Low pH is important for the maturation of sperm and their storage in a quiescent state. The V-ATPase also participates in the acidification of intracellular organelles. The V-ATPase contains many subunits, and several of these subunits have multiple isoforms. So far, only subunits ATP6V1B1, ATP6V1B2, and ATP6V1E2, previously identified as B1, B2, and E subunits, have been described in the rat epididymis. Here, we report the localization of V-ATPase subunit isoforms ATP6V1A, ATP6V1C1, ATP6V1C2, ATP6V1G1, ATP6V1G3, ATP6V0A1, ATP6V0A2, ATP6V0A4, ATP6V0D1, and ATP6V0D2, previously labeled A, C1, C2, G1, G3, a1, a2, a4, d1, and d2, in epithelial cells of the rat epididymis and vas deferens. Narrow and clear cells showed a strong apical staining for all subunits, except the ATP6V0A2 isoform. Subunits ATP6V0A2 and ATP6V1A were detected in intracellular structures closely associated but not identical to the TGN of principal cells and narrow/clear cells, and subunit ATP6V0D1 was strongly expressed in the apical membrane of principal cells in the apparent absence of other V-ATPase subunits. In conclusion, more than one isoform of subunits ATP6V1C, ATP6V1G, ATP6V0A, and ATP6V0D of the V-ATPase are present in the epididymal and vas deferens epithelium. Our results confirm that narrow and clear cells are well fit for active proton secretion. In addition, the diverse functions of the V-ATPase may be established through the utilization of specific subunit isoforms. In principal cells, the ATP6V0D1 isoform may have a physiological function that is distinct from its role in proton transport via the V-ATPase complex.
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PMID:Distinct expression patterns of different subunit isoforms of the V-ATPase in the rat epididymis. 1619

An essential aspect of male reproductive capacity is the immediate availability of fertilization-ready spermatozoa. To ensure this, most mammals rely on post-testicular sperm maturation. In epididymis, germ cells are matured and stored in a quiescent state that readily can be altered to produce active spermatozoa. This depends on active proton secretion into the epididymal lumen. We have identified Foxi1 as an important regulator of gene expression in narrow and clear cells-the major proton secretory cells of epididymal epithelia. Foxi1 appears to be required for the expression of the B1-subunit of the vacuolar H+ -ATPase proton pump and for carbonic anhydrase II as well as the chloride/bicarbonate transporter pendrin. Using transfection experiments, we have identified a Foxi1 binding cis-element in the ATP6V1B1 (encoding the B1-subunit) promoter that is critical for reporter gene activation. When this site is mutated to eliminate Foxi1 binding, activation is also abolished. As a consequence of defect Foxi1-dependent epididymal sperm maturation, we demonstrate that spermatozoa from Foxi1 null males fail to reach the female genital tract in sufficient number to allow fertilization.
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PMID:Epididymal expression of the forkhead transcription factor Foxi1 is required for male fertility. 1693 48

Proton-transporting cells are located in several tissues where they acidify the extracellular environment. These cells express the vacuolar H(+)-ATPase (V-ATPase) B1 subunit (ATP6V1B1) in their plasma membrane. We provide here a comprehensive catalog of the proteins that are expressed in these cells, after their isolation by enzymatic digestion and fluorescence-activated cell sorting (FACS) from transgenic B1-enhanced green fluorescent protein (EGFP) mice. In these mice, type A and B intercalated cells and connecting segment cells of the kidney, and narrow and clear cells of the epididymis, which all express ATP6V1B1, also express EGFP, while all other cell types are negative. The proteome of renal and epididymal EGFP-positive (EGFP(+)) cells was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and compared with their respective EGFP-negative (EGFP(-)) cell populations. A total of 2,297 and 1,564 proteins were detected in EGFP(+) cells from the kidney and epididymis, respectively. Out of these proteins, 202 and 178 were enriched by a factor greater than 1.5 in EGFP(+) cells compared with EGFP(-) cells, in the kidney and epididymis respectively, and included subunits of the V-ATPase (B1, a4, and A). In addition, several proteins involved in intracellular trafficking, signaling, and cytoskeletal dynamics were identified. A novel common protein that was enriched in renal and epididymal EGFP(+) cells is the progesterone receptor, which might be a potential candidate for the regulation of V-ATPase-dependent proton transport. These proteomic databases provide a framework for comprehensive future analysis of the common and distinct functions of V-ATPase-B1-expressing cells in the kidney and epididymis.
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PMID:Proteomic analysis of V-ATPase-rich cells harvested from the kidney and epididymis by fluorescence-activated cell sorting. 2023 46