Endocytic recycling in yeast is regulated by putative phospholipid translocases and the Ypt31p/32p-Rcy1p pathway
Endocytic recycling in yeast is regulated by putative phospholipid translocases and the Ypt31p/32p-Rcy1p pathway
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DOI：
10.1091/mbc.e06-05-0461
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发表时间：
2007-01-01
影响因子：
3.3
通讯作者：
Tanaka, Kazuma
中科院分区：
文献类型：
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作者：
Furuta, Nobumichi;Fujimura-Kamada, Konomi;Tanaka, Kazuma
磷脂移位酶（PLT）与膜双层中磷脂不对称性的产生有关。在芽殖酵母中，推定的PLT由4型P型ATP酶的DRS 2基因家族编码。同源蛋白Cdc 50 p，Lem 3 p和Crf 1 p是潜在的非催化亚基的Drs 2 p，Dnf 1 p和Dnf 2 p，和Dnf 3 p，分别这些推定的异聚体血小板共享细胞生长的基本功能。我们在lem 3 Delta crf 1 Delta背景中构建了CDC 50的温度敏感突变体（cdc 50-ts突变体）。筛选cdc 50-ts的多拷贝抑制子鉴定了YPT 31/32，这两个基因编码参与胞吐和胞吞再循环途径的Rab家族小GTP酶。cdc 50-ts突变体并没有表现出重大缺陷的外排途径，但他们表现出那些在内吞循环;大膜结构含有囊泡可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体Snc 1 p细胞内积累在这些突变体。遗传结果表明，YPT 31/32效应RCY 1和CDC 50在相同的信号通路中起作用，并且同时过表达CDC 50、DRS 2和GFP-SNC 1恢复了rcy 1 Delta突变体中的生长以及GFP-Snc 1 p的质膜定位。此外，Rcy 1 p与Cdc 50 p-Drs 2 p共免疫沉淀。我们建议，Ypt 31 p/32 p-Rcy 1 p途径调节假定的磷脂转位酶，以促进形成囊泡的目的是从早期内体的trans-Golgi网络。
Phospholipid translocases (PLTs) have been implicated in the generation of phospholipid asymmetry in membrane bilayers. In budding yeast, putative PLTs are encoded by the DRS2 gene family of type 4 P-type ATPases. The homologous proteins Cdc50p, Lem3p, and Crf1p are potential noncatalytic subunits of Drs2p, Dnf1p and Dnf2p, and Dnf3p, respectively; these putative heteromeric PLTs share an essential function for cell growth. We constructed temperature-sensitive mutants of CDC50 in the lem3 Delta crf1 Delta background (cdc50-ts mutants). Screening for multicopy suppressors of cdc50-ts identified YPT31/32, two genes that encode Rab family small GTPases that are involved in both the exocytic and endocytic recycling pathways. The cdc50-ts mutants did not exhibit major defects in the exocytic pathways, but they did exhibit those in endocytic recycling; large membranous structures containing the vesicle-soluble N-ethylmaleimide-sensitive factor attachment protein receptor Snc1p intracellularly accumulated in these mutants. Genetic results suggested that the YPT31/32 effector RCY1 and CDC50 function in the same signaling pathway, and simultaneous overexpression of CDC50, DRS2, and GFP-SNC1 restored growth as well as the plasma membrane localization of GFP-Snc1p in the rcy1 Delta mutant. In addition, Rcy1p coimmunoprecipitated with Cdc50p-Drs2p. We propose that the Ypt31p/32p-Rcy1p pathway regulates putative phospholipid translocases to promote formation of vesicles destined for the trans-Golgi network from early endosomes.