Identification of a second amphipathic lipid-packing sensor like motif that contributes to Gcs1p function in the early endosome-to-TGN pathway
Identification of a second amphipathic lipid-packing sensor like motif that contributes to Gcs1p function in the early endosome-to-TGN pathway
复制标题
鉴定第二个两亲性脂质堆积传感器样基序，该基序有助于早期内体到 TGN 途径中的 Gcs1p 功能
DOI：
10.1093/jb/mvt025
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发表时间：
2013
期刊：
影响因子：
2.7
通讯作者：
and Kazuma Tanaka
中科院分区：
文献类型：
--
作者：
Zahra Zendeh-boodi;Takaharu Yamamoto;Hiroshi Sakane;and Kazuma Tanaka
ArfGAP是Arf小GTP酶的GTP酶激活蛋白，参与各种转运途径的囊泡形成的多个步骤。两亲性脂质包装传感器（ALPS）基序首先在ArfGAP 1及其酵母同源物Gcs 1 p的C-末端区域被鉴定为通过折叠成两亲性α-螺旋（AH）而优先吸附到高度弯曲的膜上的区域。我们以前表明，Gcs 1 p功能相互作用的磷脂翻转酶Cdc 50 p-Drs 2 p在早期内体TGN检索途径。在这项研究中，我们进行了功能分析的C-末端区域的Gcs 1 p含有ALPS。疏水聚类分析表明，在Gcs 1 p的ALPS下游存在另一个潜在的AH形成区域。突变分析表明，ALPS基序是重要的Gcs 1 p功能的高尔基体-ER逆行途径，而ALPS和预测的AH区域冗余功能的后高尔基体途径，包括早期内体-TGN途径。脂质体浮选实验表明，该下游区域优先与较小尺寸的脂质体相互作用。含有ALPS基序的区域也是与SNARE蛋白（包括Snc 1 p和Tlg 1 p）相互作用所必需的。这些结果表明，ALPS和预测的AH区域参与Gcs 1 p的调节和功能，通过与膜磷脂和囊泡蛋白相互作用。
ArfGAPs, GTPase-activating proteins for Arf small GTPases, are involved in multiple steps of vesicle formation of various transport pathways. Amphipathic lipid-packing sensor (ALPS) motif was first identified in the C-terminal regions of ArfGAP1 and its yeast homologue Gcs1p as a region that adsorbs preferentially onto highly curved membranes by folding into an amphipathic α-helix (AH). We previously showed that Gcs1p functionally interacted with the phospholipid flippase Cdc50p–Drs2p in the early endosome-to-TGN retrieval pathway. In this study, we performed functional analyses of the C-terminal region of Gcs1p containing ALPS. Hydrophobic cluster analysis suggested that there is another potential AH-forming region downstream of ALPS in Gcs1p. Mutational analysis suggested that the ALPS motif is important for the Gcs1p function in the Golgi-to-ER retrograde pathway, whereas ALPS and the predicted AH region redundantly function in the post-Golgi pathways including the early endosome-to-TGN pathway. Liposome flotation assay indicated that this downstream region preferentially interacted with liposomes of smaller size. The region containing the ALPS motif was also required for the interaction with SNARE proteins including Snc1p and Tlg1p. These results suggest that ALPS and the predicted AH region are involved in the regulation and function of Gcs1p by interacting with membrane phospholipids and vesicle proteins.