HPH1 AND HPH2 ARE NOVEL COMPONENTS OF THE SEC63/SEC62 COMPLEX

HPH1 和 HPH2 是 SEC63/SEC62 复合体的新颖成分

• 批准号: 8365855
• 负责人: Martha S. Cyert
• 金额: $ 2.18万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8365855
• 关键词: ATP phosphohydrolase; Biogenesis; Biology; Cell Survival; Cells; Complex; Defect; Endoplasmic Reticulum; Exhibits; Funding; Fungal Genome; Grant; Growth; Mediating; Membrane; Membrane Proteins; Molecular; National Center for Research Resources; Phenotype; Principal Investigator; Process; Protein translocation; Proteins; Protons; Research; Research Infrastructure; Resources; Saccharomyces cerevisiae; Source; Stress; Ubiquitin; United States National Institutes of Health; Vacuole; Yeasts; base; cost; mutant; novel; yeast two hybrid system

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Hph1 and Hph2 are homologous integral endoplasmic reticulum (ER) membrane proteins required for Saccharomyces cerevisiae survival under environmental stress conditions. To investigate the molecular functions of Hph1 and Hph2, we carried out a split-ubiquitin-membrane-based yeast two-hybrid screen and identified their interactions with Sec71, a subunit of the Sec63/Sec62 complex, which mediates posttranslational translocation of proteins into the ER. Hph1 and Hph2 likely function in posttranslational translocation, as they interact with other Sec63/Sec62 complex subunits, i.e., Sec72, Sec62, and Sec63. hph1 hph2 cells display reduced vacuole acidification; increased instability of Vph1, a subunit of vacuolar proton ATPase (V-ATPase); and growth defects similar to those of mutants lacking V-ATPase activity. sec71 cells exhibit similar phenotypes, indicating that Hph1/Hph2 and the Sec63/Sec62 complex function during V-ATPase biogenesis. Hph1/Hph2 and the Sec63/Sec62 complex may act together in this process, as vacuolar acidification and Vph1 stability are compromised to the same extent in hph1 hph2 and hph1 hph2 sec71 cells. In contrast, loss of Pkr1, an ER protein that promotes posttranslocation assembly of Vph1 with V-ATPase subunits, further exacerbates hph1 hph2 phenotypes, suggesting that Hph1 and Hph2 function independently of Pkr1-mediated V-ATPase assembly. We propose that Hph1 and Hph2 aid Sec63/Sec62-mediated translocation of specific proteins, including factors that promote efficient biogenesis of V-ATPase, to support yeast cell survival during environmental stress.

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 Hph 1和Hph 2是同源的整合内质网（ER）膜蛋白所需的酿酒酵母在环境胁迫条件下的生存。为了研究Hph 1和Hph 2的分子功能，我们进行了基于分裂泛素膜的酵母双杂交筛选，并确定了它们与Sec 71的相互作用，Sec 71是Sec 63/Sec 62复合物的亚基，介导蛋白质翻译后易位到ER中。Hph 1和Hph 2可能在翻译后易位中起作用，因为它们与其他Sec 63/Sec 62复合物亚基相互作用，即，Sec72 Sec62 Sec63 hph 1 hph 2细胞显示减少液泡酸化;增加Vph 1，液泡质子ATP酶（V-ATP酶）的亚基的不稳定性;和缺乏V-ATP酶活性的突变体类似的生长缺陷。sec 71细胞表现出相似的表型，表明Hph 1/Hph 2和Sec 63/Sec 62复合体在V-ATP酶生物合成过程中起作用。Hph 1/Hph 2和Sec 63/Sec 62复合物可能在此过程中共同起作用，因为在hph 1 hph 2和hph 1 hph 2 sec 71细胞中，液泡酸化和Vph 1稳定性受到相同程度的损害。与此相反，Pkr 1，ER蛋白，促进Vph 1与V-ATP酶亚基易位后组装的损失，进一步加剧了Hph 1和Hph 2表型，表明Hph 1和Hph 2功能独立于Pkr 1介导的V-ATP酶组装。我们建议，Hph 1和Hph 2援助Sec 63/Sec 62介导的特定蛋白质的易位，包括促进V-ATP酶的有效生物合成的因素，以支持酵母细胞在环境压力下的生存。