Cytohesin-2/ARNO,through Its Interaction with Focal Adhesion Adaptor Protein Paxillin,Regulates Preadipocyte Migration via the Downstream Activation of Arf6 |
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Authors: | Tomohiro Torii Yuki Miyamoto Atsushi Sanbe Kohji Nishimura Junji Yamauchi Akito Tanoue |
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Affiliation: | From the ‡Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Okura, Tokyo 157-8535, Japan.;the ¶Department of Biological Sciences, Tokyo Institute of Technology, Midori, Yokohama 226-8501, Japan.;the §Department of Molecular and Functional Genomics, Shimane University, Matsue, Shimane 690-8504, Japan, and ;‖The Japan Health Sciences Foundation, Chuo, Tokyo 103-0001, Japan |
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Abstract: | The formation of primitive adipose tissue is the initial process in adipose tissue development followed by the migration of preadipocytes into adipocyte clusters. Comparatively little is known about the molecular mechanism controlling preadipocyte migration. Here, we show that cytohesin-2, the guanine-nucleotide exchange factor for the Arf family GTP-binding proteins, regulates migration of mouse preadipocyte 3T3-L1 cells through Arf6. SecinH3, a specific inhibitor of the cytohesin family, markedly inhibits migration of 3T3-L1 cells. 3T3-L1 cells express cytohesin-2 and cytohesin-3, and knockdown of cytohesin-2 with its small interfering RNA effectively decreases cell migration. Cytohesin-2 preferentially acts upstream of Arf6 in this signaling pathway. Furthermore, we find that the focal adhesion protein paxillin forms a complex with cytohesin-2. Paxillin colocalizes with cytohesin-2 at the leading edges of migrating cells. This interaction is mediated by the LIM2 domain of paxillin and the isolated polybasic region of cytohesin-2. Importantly, migration is inhibited by expression of the constructs containing these regions. These results suggest that cytohesin-2, through a previously unexplored complex formation with paxillin, regulates preadipocyte migration and that paxillin plays a previously unknown role as a scaffold protein of Arf guanine-nucleotide exchange factor. |
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Keywords: | Adipocyte Cell Migration Cytoskeleton Exchangers Protein-Protein Interactions Cytohesin Paxillin |
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