1. YIPF5 and YIF1A recycle between the ER and the Golgi apparatus and are involved in the maintenance of the Golgi structure.
- Author
-
Yoshida Y, Suzuki K, Yamamoto A, Sakai N, Bando M, Tanimoto K, Yamaguchi Y, Sakaguchi T, Akhter H, Fujii G, Yoshimura S, Ogata S, Sohda M, Misumi Y, and Nakamura N
- Subjects
- Endoplasmic Reticulum ultrastructure, Fluorescent Antibody Technique, Golgi Apparatus ultrastructure, HeLa Cells, Humans, Membrane Proteins analysis, Membrane Proteins genetics, Microscopy, Immunoelectron, Protein Transport, Vesicular Transport Proteins analysis, Vesicular Transport Proteins genetics, Endoplasmic Reticulum metabolism, Golgi Apparatus metabolism, Membrane Proteins metabolism, Vesicular Transport Proteins metabolism
- Abstract
Yip1p/Yif1p family proteins are five-span transmembrane proteins localized in the Golgi apparatus and the ER. There are nine family members in humans, and YIPF5 and YIF1A are the human orthologs of budding yeast Yip1p and Yif1p, respectively. We raised antisera against YIPF5 and YIF1A and examined the localization of endogenous proteins in HeLa cells. Immunofluorescence, immunoelectron microscopy and subcellular fractionation analysis suggested that YIPF5 and YIF1A are not restricted to ER exit sites but also localized in the ER-Golgi intermediate compartment (ERGIC) and some in the cis-Golgi at steady state. Along with ERGIC53, YIPF5 and YIF1A remained in the cytoplasmic punctate structures after brefeldin A treatment, accumulated in the ERGIC and the cis-Golgi after treatment with AlF4- and accumulated in the ER when ER to Golgi transport was inhibited by Sar1(H79G). These results supported the localization of YIPF5 and YIF1A in the ERGIC and the cis-Golgi, and strongly suggested that they are recycling between the ER and the Golgi apparatus. Analysis by blue native PAGE and co-immunoprecipitation showed that YIPF5 and YIF1A form stable complexes of three different sizes. Interestingly, the knockdown of YIPF5 or YIF1A caused partial disassembly of the Golgi apparatus suggesting that YIPF5 and YIF1A are involved in the maintenance of the Golgi structure.
- Published
- 2008
- Full Text
- View/download PDF