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Updated: Jul 17, 2026

RhoC GTPase Activation Assay
Published on: August 22, 2010
Selective glucocorticoid control of Rho kinase isoforms regulate cell-cell interactions
Nicola M Rubenstein1, Joseph A Callahan, Daniel H Lo
1Department of Molecular and Cell Biology, The Cancer Research Laboratory, University of California at Berkeley, 591 LSA, Berkeley, CA 94720-3200, USA.
Glucocorticoids like dexamethasone differentially regulate Rho kinase (ROCK) isoforms. ROCK2 expression and activity increase, while ROCK1 activity decreases, impacting tight junction formation.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Rho kinase (ROCK) isoforms ROCK1 and ROCK2 are effectors of RhoA.
- Isoform-specific functions and regulation of ROCK1 and ROCK2 remain largely uncharacterized.
Purpose of the Study:
- To investigate the isoform-specific effects of glucocorticoids on ROCK1 and ROCK2.
- To elucidate the role of ROCK isoforms in glucocorticoid-mediated tight junction formation.
Main Methods:
- Utilized Con8 rat mammary epithelial cells.
- Administered synthetic glucocorticoid dexamethasone.
- Assessed ROCK1 and ROCK2 protein levels and kinase activity.
- Measured RhoA activity and Rnd3 function.
- Employed ROCK inhibitor Y-27632.
Main Results:
- Dexamethasone increased ROCK2 protein levels and activity.
- Steroid treatment decreased ROCK1 kinase activity without changing protein levels.
- Glucocorticoid-induced tight junction formation required RhoA downregulation and Rnd3.
- ROCK inhibition blocked glucocorticoid- and Rnd3-mediated tight junction sealing.
Conclusions:
- ROCK1 and ROCK2 expression and activity can be uncoupled in a signal-dependent manner.
- ROCK2 plays a novel role in steroid-controlled tight junction dynamics.
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