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CCK-A receptor activates RhoA through G alpha 12/13 in NIH3T3 cells
Sophie L Le Page1, Yan Bi, John A Williams
1Department. of Molecular & Integrative Physiology, University of Michigan, 7744 Medical Science II, Ann Arbor, MI 48109-0622, USA.
American Journal of Physiology. Cell Physiology
|July 11, 2003
Summary
Cholecystokinin (CCK) activates RhoA and actin stress fibers via G13 signaling in NIH3T3 cells. This mechanism reveals CCK
Area of Science:
- Cell Biology
- Molecular Signaling
- Cytoskeleton Dynamics
Background:
- Cholecystokinin (CCK) regulates pancreatic acinar cells and influences cellular cytoskeleton.
- CCK-A receptors are present in various cell types, including NIH3T3 cells.
Purpose of the Study:
- To investigate the mechanism by which CCK induces cytoskeletal changes in NIH3T3 cells expressing CCK-A receptors.
- To identify the specific G protein and RhoA pathway involved in CCK-mediated actin remodeling.
Main Methods:
- Utilized NIH3T3 cells stably transfected with CCK-A receptors.
- Employed RhoA activation assays (pull-down, SRE-luciferase reporter).
- Investigated G protein involvement using transfected active alpha-subunits and RGS domains.
Main Results:
- CCK induced actin stress fibers rapidly, dependent on G13 and RhoA.
- CCK triggered RhoA activation, mimicked by constitutively active RhoV14 and blocked by Rho inhibitors.
- Galpha13, but not Galphaq, mediated CCK-induced stress fibers, further confirmed by RGS domain and peptide inhibition studies.
Conclusions:
- CCK activates RhoA primarily through the G13 protein in NIH3T3 cells with CCK-A receptors.
- This signaling pathway leads to the rearrangement of the actin cytoskeleton.
- The findings elucidate a novel CCK signaling cascade impacting cellular structure.