JCB logo
Accuri Cytometers
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
Published online 7 March 2005. doi:10.1083/jcb.200408182
The Rockefeller University Press, 0021-9525 $8.00
JCB, Volume 168, Number 6, 921-928
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 1966K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Yamada, E.
Right arrow Articles by Mori, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yamada, E.
Right arrow Articles by Mori, M.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Article

Akt2 phosphorylates Synip to regulate docking and fusion of GLUT4-containing vesicles



Eijiro Yamada1, Shuichi Okada1, Tsugumichi Saito1, Kihachi Ohshima2, Minoru Sato1, Takafumi Tsuchiya1, Yutaka Uehara1, Hiroyuki Shimizu1, and Masatomo Mori1,3

1 Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
2 Health and Science Center, Gunma University, Maebashi, Gunma, 371-8510, Japan
3 Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi, Saitama 332-0012, Japan

Correspondence to Shuichi Okada: okadash{at}showa.gunma-u.ac.jp

We have identified an unusual potential dual Akt/protein kinase B consensus phosphorylation motif in the protein Synip (RxKxRS97xS99). Surprisingly, serine 97 is not appreciably phosphorylated, whereas serine 99 is only a specific substrate for Akt2 but not Akt1 or Akt3. Although wild-type Synip (WT-Synip) undergoes an insulin-stimulated dissociation from Syntaxin4, the Synip serine 99 to phenylalanine mutant (S99F-Synip) is resistant to Akt2 phosphorylation and fails to display insulin-stimulated Syntaxin4 dissociation. Furthermore, overexpression of WT-Synip in 3T3L1 adipocytes had no effect on insulin-stimulated recruitment of glucose transporter 4 (GLUT4) to the plasma membrane, whereas overexpression of S99F-Synip functioned in a dominant-interfering manner by preventing insulin-stimulated GLUT4 recruitment and plasma membrane fusion. These data demonstrate that insulin activation of Akt2 specifically regulates the docking/fusion step of GLUT4-containing vesicles at the plasma membrane through the regulation of Synip phosphorylation and Synip–Syntaxin4 interaction.

Abbreviations used in this paper: GLUT4, glucose transporter 4; GSK3, glycogen synthesis kinase 3; PI3, phosphatidylinositol 3; siRNA, small interfering RNA; WT, wild-type.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents