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Updated: Jul 16, 2026
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Oligopeptide Competition Assay for Phosphorylation Site Determination
Published on: May 18, 2017
The Par6alpha/aPKC complex regulates Akt1 activity by phosphorylating Thr34 in the PH-domain
P Weyrich1, D Neuscheler, M Melzer
1Department of Internal Medicine IV, University of Tübingen, Otfried-Müller-Str. 10, D-72076 Tübingen, Germany.
Molecular and Cellular Endocrinology
|March 6, 2007
Summary
Par6alpha inhibits insulin-stimulated Akt1 activation and glycogen synthesis in muscle cells. This effect requires Par6alpha to interact with aPKC and phosphorylate Akt1 at T34.
Area of Science:
- Cellular biology
- Molecular biology
- Metabolism
Background:
- A polymorphism in the Par6alpha promoter correlates with lower expression and improved insulin sensitivity.
- Par6alpha overexpression in C2C12 myoblasts impairs insulin signaling and glucose uptake.
Purpose of the Study:
- To elucidate the mechanism by which Par6alpha inhibits insulin-induced Akt1 activation and glycogen synthesis.
- To investigate the role of the interaction between Par6alpha and aPKC in this inhibitory process.
Main Methods:
- Utilized C2C12 myoblasts and a DeltaPB1-Par6alpha deletion mutant.
- Assessed protein kinase B/Akt1 activation and glycogen synthesis following insulin stimulation.
- Examined the effect of Par6alpha overexpression on wild-type and T34A-Akt1 mutants.
Main Results:
- Direct interaction between Par6alpha and atypical protein kinase C (aPKC) is essential for inhibiting insulin-induced Akt1 activation.
- T34 phosphorylation of Akt1 by aPKC is critical for this inhibition.
- Overexpression of Par6alpha reduced wild-type Akt1 activation but not T34A-Akt1, restoring insulin-induced glycogen synthesis.
Conclusions:
- Par6alpha-mediated inhibition of insulin-dependent glycogen synthesis in C2C12 cells relies on its interaction with aPKC.
- aPKC-mediated T34 phosphorylation of Akt1 is a key step in this inhibitory pathway.
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