Roles of phosphoinositides and of Spo14p (phospholipase D)-generated phosphatidic acid during yeast sporulation.
Roles of phosphoinositides and of Spo14p (phospholipase D)-generated phosphatidic acid during yeast sporulation.
复制标题
磷酸肌醇和 Spo14p（磷脂酶 D）生成的磷脂酸在酵母孢子形成过程中的作用。
DOI：
10.1091/mbc.e03-04-0245
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发表时间：
2004
影响因子：
3.3
通讯作者：
Engebrecht,JoAnne
中科院分区：
文献类型：
--
作者：
Rudge,SimonA;Sciorra,VickiA;Iwamoto,Michelle;Zhou,Chun;Strahl,Thomas;Morris,AndrewJ;Thorner,Jeremy;Engebrecht,JoAnne
在酵母孢子形成期间，内膜合成确保每个单倍体核被包装成孢子。前孢子膜的形成需要Spo 14 p，一种磷脂酰肌醇4，5-二磷酸[PtdIns（4，5）P2]刺激的磷脂酶D（PLD），其将磷脂酰胆碱（PtdCho）水解为磷脂酸（PtdOH）和胆碱。我们发现减数分裂和孢子形成也需要磷脂酰肌醇（PtdIns）/PtdCho转运蛋白Sec 14 p。Sec 14 p的PtdIns运输活性的特异性消融足以损害孢子形成，但不损害减数分裂。PtdIns 4-激酶Pik 1 p的过表达抑制了这些ec 14 - 1减数分裂和孢子形成缺陷;相反，pik 1-ts二倍体不能进行减数分裂和孢子形成。PtdIns（4）P5-激酶Mss 4p也是孢子形成所必需的。使用磷酸肌醇特异性GFP-PH结构域报告证实PtdIns（4，5）P2富集在原孢子膜上。sec 14、pik 1和mss 4突变体显示Spo 14 p PLD活性降低，而Spo 14 p缺失不影响体内磷酸肌醇水平，表明PtdIns（4，5）P2的形成对Spo 14 p活性很重要。Spo 14 p产生的PtdOH似乎在孢子形成中具有重要作用，因为用1-丁醇处理细胞，其支持Spo 14 p催化的PtdCho分解，但导致Cho和Ptd-丁醇的产生，在惰性异构体2-丁醇几乎没有影响的浓度下阻断孢子形成。因此，我们的研究结果表明，在孢子形成过程中，Spo 14 p介导的PtdOH产生在Sec 14 p、Pik 1 p和Mss 4p依赖的PtdIns（4，5）P2合成的下游发挥作用，而不是PtdOH刺激PtdIns（4，5）P2形成的作用。
During yeast sporulation, internal membrane synthesis ensures that each haploid nucleus is packaged into a spore. Prospore membrane formation requires Spo14p, a phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]-stimulated phospholipase D (PLD), which hydrolyzes phosphatidylcholine (PtdCho) to phosphatidic acid (PtdOH) and choline. We found that both meiosis and spore formation also require the phosphatidylinositol (PtdIns)/PtdCho transport protein Sec14p. Specific ablation of the PtdIns transport activity of Sec14p was sufficient to impair spore formation but not meiosis. Overexpression of Pik1p, a PtdIns 4-kinase, suppressed thesec14-1meiosis and spore formation defects; conversely,pik1-tsdiploids failed to undergo meiosis and spore formation. The PtdIns(4)P 5-kinase, Mss4p, also is essential for spore formation. Use of phosphoinositide-specific GFP-PH domain reporters confirmed that PtdIns(4,5)P2is enriched in prospore membranes.sec14, pik1,andmss4mutants displayed decreased Spo14p PLD activity, whereas absence of Spo14p did not affect phosphoinositide levels in vivo, suggesting that formation of PtdIns(4,5)P2is important for Spo14p activity. Spo14p-generated PtdOH appears to have an essential role in sporulation, because treatment of cells with 1-butanol, which supports Spo14p-catalyzed PtdCho breakdown but leads to production of Cho and Ptd-butanol, blocks spore formation at concentrations where the inert isomer, 2-butanol, has little effect. Thus, rather than a role for PtdOH in stimulating PtdIns(4,5)P2formation, our findings indicate that during sporulation, Spo14p-mediated PtdOH production functions downstream of Sec14p-, Pik1p-, and Mss4p-dependent PtdIns(4,5)P2synthesis.