An essential subfamily of Drs2p-related P-type ATPases is required for protein trafficking between Golgi complex and endosomal/vacuolar system
An essential subfamily of Drs2p-related P-type ATPases is required for protein trafficking between Golgi complex and endosomal/vacuolar system
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DOI：
10.1091/mbc.e02-03-0172
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发表时间：
2002-09-01
影响因子：
3.3
通讯作者：
Graham, TR
中科院分区：
文献类型：
--
作者：
Hua, ZL;Fatheddin, P;Graham, TR
酿酒酵母基因组包含5个编码p型atp酶的基因，这些atp酶是潜在的氨基磷脂转位酶（APTs）： DRS2、NEO1，以及我们命名为DRS21NEO1家族的三个未表征的开放阅读框DNF1、DNF2和DNF3。NEO1是APT家族中唯一的必需基因，在功能上似乎与DRS2/DNF基因不同。drs2Delta dnflDelta dnf2Delta dnf3Delta四重突变体是不可存活的，尽管该组中的任何一个成员都可以保持生存能力，这表明编码蛋白之间存在大量的功能重叠。我们先前已经暗示Drs2p在反式高尔基网络中的网格蛋白功能。在这项研究中，我们构建了携带所有可能的零等位基因组合的菌株，并分析了它们在蛋白质运输方面的缺陷。drs2Delta dnf1Delta突变体生长缓慢，在细胞膜内大量积聚，并且在碱性磷酸酶向液泡的运输中表现出明显的缺陷。羧基肽酶Y向液泡的转运也受到干扰，但程度较轻。此外，dnf1Delta dnf2Delta dnf3Delta突变体在早期内吞-晚期分泌途径中表现出GFP-Snc1p循环的缺陷。Drs2p和Dnf3p与反式高尔基网络标记物Kex2p共定位，而Dnf1p和Dnf2p似乎定位于质膜和胞外晚期或早期内吞噬膜。我们提出真核生物表达多个APT亚家族成员以促进蛋白质在多种途径中的转运。
The Saccharomyces cerevisiae genome contains five genes encoding P-type ATPases that are potential aminophospholipid translocases (APTs): DRS2, NEO1, and three uncharacterized open reading frames that we have named DNF1, DNF2, and DNF3 for DRS21NEO1 family. NEO1 is the only essential gene in APT family and seems to be functionally distinct from the DRS2/DNF genes. The drs2Delta dnflDelta dnf2Delta dnf3Delta quadruple mutant is inviable, although any one member of this group can maintain viability, indicating that there is a substantial functional overlap between the encoded proteins. We have previously implicated Drs2p in clathrin function at the trans-Golgi network. In this study, we constructed strains carrying all possible viable combinations of null alleles from this group and analyzed them for defects in protein transport. The drs2Delta dnf1Delta mutant grows slowly, massively accumulates intracellular membranes, and exhibits a substantial defect in the transport of alkaline phosphatase to the vacuole. Transport of carboxypeptidase Y to the vacuole is also perturbed, but to a lesser extent. In addition, the dnf1Delta dnf2Delta dnf3Delta mutant exhibits a defect in recycling of GFP-Snc1p in the early endocytic-late secretory pathways. Drs2p and Dnf3p colocalize with the trans-Golgi network marker Kex2p, whereas Dnf1p and Dnf2p seem to localize to the plasma membrane and late exocytic or early endocytic membranes. We propose that eukaryotes express multiple APT subfamily members to facilitate protein transport in multiple pathways.