Related Experiment Video
Updated: Jul 16, 2026

Measurement of Insulin- and Contraction-Stimulated Glucose Uptake in Isolated and Incubated Mature Skeletal Muscle from Mice
Published on: May 16, 2021
Synip phosphorylation is required for insulin-stimulated Glut4 translocation
Shuichi Okada1, Kihachi Ohshima, Yutaka Uehara
1Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, 3-39-15, Showa-machi, Maebashi, Gunma 371-8511, Japan. okadash@showa.gunma-u.ac.jp
Abstract:
Previously we identified an unusual potential dual Akt/protein kinase B consensus phosphorylation motif in the protein Synip (RxKxRS(97)xS(99)) 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.
Related Concept Videos
Insulin: The Receptor and Signaling Pathways
Insulin Secretory Vesicles
Glucose Homeostasis: Pancreatic Islets and Insulin Secretion
Insulin and C-peptide are co-secreted in...
cAMP-dependent Protein Kinase Pathways
PI3K/mTOR/AKT Signaling Pathway
Hormones Regulating Blood Glucose
In addition to accelerating glucose uptake and utilization, insulin has...

