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IQGAP1 regulates cell proliferation through a novel CDC42-mTOR pathway
Jian-Bin Wang1, Robert Sonn, Yemmsrach K Tekletsadik
1Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA.
Journal of Cell Science
|May 21, 2009
Summary
IQGAP1 regulates cell proliferation by coordinating cell growth and division via a novel CDC42-mTOR pathway. Phosphorylation and CDC42 binding are crucial for IQGAP1
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Cell proliferation necessitates coordinated cell growth and division for size maintenance.
- IQGAP1, a CDC42 effector, influences cell architecture, exocytosis, and cancer, but its precise mechanism is unknown.
Purpose of the Study:
- To elucidate the mechanism by which IQGAP1 regulates cell proliferation.
- To investigate the role of IQGAP1 phosphorylation and CDC42 binding in proliferation.
- To identify novel pathways involving IQGAP1 in cell growth and division.
Main Methods:
- Investigated IQGAP1 function through expression of its N-terminal and C-terminal regions.
- Analyzed IQGAP1 phosphorylation and binding to CDC42.
- Examined the interaction between IQGAP1 and mTOR.
- Assessed effects on cell size, transformation, and migration.
Main Results:
- IQGAP1 regulates cell proliferation, dependent on its phosphorylation and CDC42 binding.
- C-terminal IQGAP1 expression promoted transformation and migration while reducing cell size.
- N-terminal IQGAP1 expression increased cell size but inhibited transformation and migration.
- IQGAP1 interacts with mTOR, a requirement for IQGAP1-mediated cell proliferation.
Conclusions:
- IQGAP1 acts as a phosphorylation-sensitive switch, coupling cell growth and division.
- A novel CDC42-mTOR pathway mediated by IQGAP1 regulates cell proliferation.
- Dysregulation of this pathway contributes to cellular transformation.
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