Reversible association between the V1 and V0 domains of yeast vacuolar H+-ATPase is an unconventional glucose-induced effect
Reversible association between the V1 and V0 domains of yeast vacuolar H+-ATPase is an unconventional glucose-induced effect
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DOI：
10.1128/mcb.18.12.7064
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发表时间：
1998-12-01
影响因子：
5.3
通讯作者：
Kane, PM
中科院分区：
文献类型：
--
作者：
Parra, KJ;Kane, PM
酵母液泡H+-ATP酶（V-ATP酶）是一种多亚基复合体，负责细胞器的酸化。该酶在结构上被组织成两个主要结构域：包含ATP结合位点的外周结构域（V-1）和形成质子孔的完整膜结构域（V-0）。V-1和V-0结构域的解离抑制ATP驱动的质子泵，并且细胞外葡萄糖浓度通过调节V-1和V-0结构域之间的缔合程度来调节体内V-ATP酶活性。为了研究这种反应的机制，我们定量了各种突变体中V-ATP酶组装的程度，这些突变体对其他葡萄糖反应过程具有已知的影响。葡萄糖对V-ATP酶组装的影响不涉及Ras-环AMP途径、Snf 1 p、蛋白激酶C或一般应激反应蛋白Rts 1 p。葡萄糖B-磷酸的积累不足以维持或诱导V-ATP酶的组装，表明需要进一步的葡萄糖代谢。葡萄糖剥夺时ATP浓度的短暂降低足以迅速触发V-ATP酶的分解，但葡萄糖再补充时细胞ATP浓度的增加不能解释重组。在缺乏ATP酶和质子泵活性的两种突变酶中，或在存在特异性V-ATP酶抑制剂康卡霉素A的情况下，抑制ATP酶。我们提出葡萄糖对V-ATP酶组装的影响是通过一种新的机制发生的，该机制需要葡萄糖代谢超过葡萄糖6-磷酸的形成，并产生一个信号，该信号只能由催化活性的V-ATP酶有效地感知。
The yeast vacuolar H+-ATPase (V-ATPase) is a multisubunit complex responsible for organelle acidification. The enzyme is structurally organized into two major domains: a peripheral domain (V-1), containing the ATP binding sites, and an integral membrane domain (V-0), forming the proton pore. Dissociation of the V-1 and V-0 domains inhibits ATP-driven proton pumping, and extracellular glucose concentrations regulate V-ATPase activity in vivo by regulating the extent of association between the V-1 and V-0 domains. To examine the mechanism of this response, we quantitated the extent of V-ATPase assembly in a variety of mutants with known effects on other glucose responsive processes, Glucose effects on V-ATPase assembly did not involve the Ras-cyclic AMP pathway, Snf1p, protein kinase C, or the general stress response protein Rts1p. Accumulation of glucose B-phosphate was insufficient to maintain or induce assembly of the V-ATPase, suggesting that further glucose metabolism is required. A transient decrease in ATP concentration with glucose deprivation occurs quickly enough to help trigger disassembly of the V-ATPase, but increases in cellular ATP concentrations with glucose readdition cannot account for reassembly. Disassembly was inhibited in two mutant enzymes lacking ATPase and proton pumping activities or in the presence of the specific V-ATPase inhibitor, concanamycin A. We propose that glucose effects on V-ATPase assembly occur by a novel mechanism that requires glucose metabolism beyond formation of glucose 6-phosphate and generates a signal that can be sensed efficiently only by a catalytically competent V-ATPase.