YIPF5 and YIF1A recycle between the ER and the Golgi apparatus and are involved in the maintenance of the Golgi structure.
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.
Yoshida
Yumi
Y
Division of Life Sciences, Graduate School of Natural Science and Technology and Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan.
Suzuki
Kurumi
K
Yamamoto
Akitsugu
A
Sakai
Noriko
N
Bando
Misako
M
Tanimoto
Kouji
K
Yamaguchi
Youko
Y
Sakaguchi
Tomoaki
T
Akhter
Hasina
H
Fujii
Gourou
G
Yoshimura
Shin-ichiro
S
Ogata
Shigenori
S
Sohda
Miwa
M
Misumi
Yoshio
Y
Nakamura
Nobuhiro
N
D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D016253:Microscopy, Immunoelectron; D021381:Protein Transport; D033921:Vesicular Transport Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
D008565:Membrane Proteins; D033921:Vesicular Transport Proteins; C503565:YIF1A protein, human; C502736:YIPF5 protein, human