Yeast Sec14p deficient in phosphatidylinositol transfer activity is functional in vivo
Yeast Sec14p deficient in phosphatidylinositol transfer activity is functional in vivo
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DOI：
10.1016/s1097-2765(00)80366-4
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发表时间：
1999-08-01
期刊：
影响因子：
16
通讯作者：
Bankaitis, VA
中科院分区：
文献类型：
--
作者：
Phillips, SE;Sha, BD;Bankaitis, VA
酵母磷脂酰肌醇转运蛋白（Sec 14 p）是高尔基体分泌功能所必需的。磷脂酰肌醇在膜之间的转移代表了磷脂酰肌醇转移蛋白（PITP）的生理活性，这一点已被广泛接受，但尚未得到证实。我们报告说，Sec 14 p（K66，239 A）是失活的磷脂酰肌醇，但不是磷脂酰胆碱（PC），转移活性。正如预期的那样，Sec 14 p（K66，239 A）不能满足体外PITP的既定标准，也不能刺激体内磷酸肌醇的产生。然而，其表达有效地挽救了与sec 14 -1（ts）和sec 14无效突变相关的致死性和高尔基体分泌缺陷。这种互补作用既不需要磷脂酶D激活，也不需要一类新的次要酵母PITP的参与。这些发现表明PI结合/转移对于Sec 14 p在体内的功能是显著不利的。
Yeast phosphatidylinositol transfer protein (Sec14p) is essential for Golgi secretory function. It is widely accepted, though unproven, that phosphatidylinositol transfer between membranes represents the physiological activity of phosphatidylinositol transfer proteins (PITPs). We report that Sec14p(K66,239A) is inactivated for phosphatidylinositol, but not phosphatidylcholine (PC), transfer activity. As expected, Sec14p(K66,239A) fails to meet established criteria for a PITP in vitro and fails to stimulate phosphoinositide production in vivo. However, its expression efficiently rescues the lethality and Golgi secretory defects associated with sec14-1(ts) and sec14 null mutations. This complementation requires neither phospholipase D activation nor the involvement of a novel class of minor yeast PITPs. These findings indicate that PI binding/transfer is remarkably dispensable for Sec14p function in vivo.