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.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 HPH1和HPH2是在环境应力条件下酿酒酵母生存所需的同源整体内质网（ER）膜蛋白。为了研究HPH1和HPH2的分子功能，我们进行了一个分裂 - 泛素 - 膜膜的酵母两杂化筛选，并确定了它们与Sec71的相互作用，Sec71是SEC63/SEC62复合物的亚基，该子单位介导了蛋白质后蛋白质转移到ER中的转移后。 HPH1和HPH2可能在翻译后易位，因为它们与其他SEC63/SEC62复杂亚基相互作用，即SEC72，SEC62和SEC63。 HPH1 HPH2细胞显示液泡酸化降低； VPH1的不稳定性增加，液泡质子ATPase的亚基（V-ATPase）；与缺乏V-ATPase活性的突变体类似的生长缺陷。 SEC71细胞表现出相似的表型，表明在V-ATPase生物发生过程中，HPH1/HPH2和SEC63/SEC62复合功能。 HPH1/HPH2和SEC63/SEC62复合物可以在此过程中起作用，因为在HPH1 HPH2和HPH1 HPH2 SEC71细胞中，液泡酸化和VPH1稳定性受到相同程度的损害。相反，PKR1的丢失是一种ER蛋白，可促进VPH1与V-ATPase亚基的转换后组装，进一步加剧了HPH1 HPH2表型，这表明HPH1和HPH2与PKR1介导的V-ATPase组装独立于PKR1和HPH2。我们建议HPH1和HPH2 AID SEC63/SEC62介导的特定蛋白质易位，包括促进V-ATPase有效生物发生的因素，以支持环境应激期间的酵母细胞存活。