Sun-Wada Ge-Hong, Tabata Hiroyuki, Kawamura Nobuyuki, Futai Masamitsu, Wada Yoh
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyotanabe, 610-0395, Japan.
Cell Tissue Res. 2007 Aug;329(2):239-48. doi: 10.1007/s00441-007-0421-7. Epub 2007 May 12.
Vacuolar-type proton ATPase (V-ATPase) is a multi-subunit enzyme that couples ATP hydrolysis to the translocation of protons across membranes. Mammalian cells express four isoforms of the a subunit of V-ATPase. Previously, we have shown that V-ATPase with the a3 isoform is highly expressed in pancreatic islets and is located in the membranes of insulin-containing granules in the beta cells. The a3 isoform functions in the regulation of hormone secretion. In this study, we have examined the distribution of a subunit isoforms in endocrine tissues, including the adrenal, parathyroid, thyroid, and pituitary glands, with isoform-specific antibodies. We have found that the a3 isoform is strongly expressed in all these endocrine tissues. Our results suggest that functions of the a3 isoform are commonly involved in the process of exocytosis in regulated secretion.
液泡型质子ATP酶（V-ATP酶）是一种多亚基酶，它将ATP水解与质子跨膜转运偶联起来。哺乳动物细胞表达V-ATP酶a亚基的四种同工型。此前，我们已经表明，具有a3同工型的V-ATP酶在胰岛中高度表达，并且位于β细胞中含胰岛素颗粒的膜上。a3同工型在激素分泌的调节中发挥作用。在本研究中，我们用同工型特异性抗体检测了a亚基同工型在内分泌组织中的分布，这些内分泌组织包括肾上腺、甲状旁腺、甲状腺和垂体。我们发现a3同工型在所有这些内分泌组织中均强烈表达。我们的结果表明，a3同工型的功能通常参与调节性分泌中的胞吐过程。
