Insulin Phosphorylation of Munc18c Affects GLUT4 Transport
Author Information
Author(s): Aran Veronica, Bryant Nia J, Gould Gwyn W
Primary Institution: University of Glasgow
Hypothesis
Tyrosine phosphorylation of Munc18c is responsible for the observed insulin-dependent abrogation of binding between Munc18c and Syntaxin 4.
Conclusion
Insulin-stimulated tyrosine phosphorylation of Munc18c impairs its ability to bind SNARE proteins, which may regulate GLUT4 trafficking.
Supporting Evidence
- Munc18c is directly phosphorylated by recombinant insulin receptor tyrosine kinase in vitro.
- Phosphorylation abrogates binding of Munc18c to both Syntaxin 4 and VAMP2.
- A phosphomimetic mutation in Munc18c also prevents binding to Syntaxin 4 and VAMP2.
- Insulin treatment leads to a significant increase in tyrosine phosphorylation of Munc18c.
Takeaway
When insulin is present, a protein called Munc18c gets a special tag that stops it from sticking to other important proteins, helping sugar get into cells.
Methodology
The study used in vitro assays to test the phosphorylation of Munc18c by insulin receptor tyrosine kinase and its binding interactions with Syntaxin 4 and VAMP2.
Limitations
The study primarily focuses on in vitro conditions, which may not fully replicate in vivo interactions.
Digital Object Identifier (DOI)
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