Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1938632 | Biochemical and Biophysical Research Communications | 2007 | 5 Pages |
Abstract
Previously we identified an unusual potential dual Akt/protein kinase B consensus phosphorylation motif in the protein Synip (RxKxRS97xS99) with serine 99 as a unique Akt2, but not Akt1 or for Akt3, substrate phosphorylation site. Although we have previously reported that serine 99 to phenylalanine (S99F-Synip) resulted in a constitutive inhibition of insulin-stimulated Glut4 translocation, a recent report indicated that Synip serine 99 to alanine mutant (S99A-Synip) failed to inhibit insulin-stimulated Glut4 translocation [H. Sano, S. Kane, E. Sano, G.E. Lienhard, Synip phosphorylation does not regulate insulin-stimulated GLUT4 translocation, Biochem. Biophys. Res. Commun. 332 (2005) 880--884]. To address this apparent discrepancy, we have now examined the S99A-Synip mutant and find that this mutant behaves essentially identical to S99F-Synip in that overexpression inhibits insulin-stimulated Glut4 translocation and is incapable of undergoing insulin-stimulated Syntaxin4 dissociation. These data are consistent with Synip serine 99 phosphorylation required for insulin-stimulated Glut4 translocation.
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Authors
Shuichi Okada, Kihachi Ohshima, Yutaka Uehara, Hiroyuki Shimizu, Koshi Hashimoto, Masanobu Yamada, Masatomo Mori,