The proton electrochemical gradient across the plasma membrane of yeast is necessary for phospholipid flip.
The proton electrochemical gradient across the plasma membrane of yeast is necessary for phospholipid flip.
复制标题
穿过酵母质膜的质子电化学梯度对于磷脂翻转是必要的。
DOI：
10.1074/jbc.m700454200
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Nichols,JWylie
中科院分区：
文献类型：
--
作者：
Stevens,HaleyC;Nichols,JWylie
最近，两个P型ATP酶P4家族成员，Dnf 1 p和Dnf 2 p，被证明是必要的内在化（翻转）的荧光，7-硝基苯-2-氧杂-1，3-二氮唑-4-基（NBD）标记的磷脂穿过质膜的酿酒酵母。在目前的研究中，我们已经证明，ATP水解是不够的磷脂翻转的质子电化学梯度跨质膜的情况下。这一要求通过两种独立的方法得到证明。首先，质子载体，羰基氰化物-氯苯腙（CCCP）的质膜质子电化学梯度的崩溃几乎完全阻止NBD-磷脂翻转，而只有适度降低胞浆ATP浓度。第二，在编码产生质子电化学梯度的质膜质子泵的PMA 1中具有点突变的菌株在NBD-PC翻转中有缺陷，而它们的胞质ATP含量实际上增加。这些结果确定了NBD-磷脂翻转穿过酵母质膜所需的质子电化学梯度，并提出了一个问题，即它是否提供了额外的所需驱动力，或者它是否起着调节信号的作用。
Recently, two members of the P4 family of P-type ATPases, Dnf1p and Dnf2p, were shown to be necessary for the internalization (flip) of fluorescent, 7-nitrobenz-2-oxa-1,3-diazol-4-yl(NBD)-labeled phospholipids across the plasma membrane ofSaccharomyces cerevisiae. In the current study, we have demonstrated that ATP hydrolysis is not sufficient for phospholipid flip in the absence of the proton electrochemical gradient across the plasma membrane. This requirement was demonstrated by two independent means. First, collapse of the plasma membrane proton electrochemical gradient by the protonophore, carbonyl cyanidem-chlorophenylhydrazone (CCCP) almost completely blocked NBD-phospholipid flip while only moderately reducing the cytosolic ATP concentration. Second, strains with point mutations inPMA1, which encodes the plasma membrane proton pump that generates the proton electrochemical gradient, are defective in NBD-PC flip, whereas their cytosolic ATP content is actually increased. These results establish that the proton electrochemical gradient is required for NBD-phospholipid flip across the plasma membrane of yeast and raise the question whether it contributes an additional required driving force or whether it functions as a regulatory signal.