Related Experiment Video
Updated: Jul 26, 2026

RhoC GTPase Activation Assay
Published on: August 22, 2010
HSP27 modulates agonist-induced association of translocated RhoA and PKC-alpha in muscle cells of the colon
K N Bitar1, A Ibitayo, S B Patil
1Department of Pediatrics, University of Michigan Medical Center, Ann Arbor, Michigan 48109, USA. bitar@umich.edu
Abstract:
The recruitment of signal transduction molecules to the membrane is crucial for the efficient coupling of extracellular signals and contractile response. The trafficking is dynamic. We have investigated a possible cross talk between agonist-induced association of translocated RhoA and translocated protein kinase C-alpha (PKC-alpha) and a role for heat shock protein 27 (HSP27) in mediating this interaction. Immunoprecipitation with HSP27 monoclonal antibody followed by immunoblotting with either RhoA antibody or PKC-alpha antibody indicated that acetylcholine induced associations of HSP27-RhoA and HSP27-PKC-alpha in the membrane fraction but not in the cytosolic fraction. Immunoprecipitation with anti-RhoA monoclonal antibody followed by immunoblotting with PKC-alpha antibody indicated that acetylcholine induced a significant complexing of RhoA-PKC-alpha in the membrane fraction but not in the cytosolic fraction. In summary, the data indicate that agonist-induced contraction is associated with 1) association of translocated RhoA with HSP27 on the membrane, 2) association of translocated PKC-alpha with HSP27 on the membrane, and 3) association of PKC-alpha with RhoA on the membrane. The data suggest an important role for HSP27 in modulating a multiprotein complex that includes translocated RhoA and PKC-alpha.
Related Concept Videos
Microtubule Associated Proteins (MAPs)
The Ras Gene
Ras is a superfamily...
Cell Polarization by Rho Proteins
Interactions Between Signaling Pathways
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
Small GTPases - Ras and Rho
Three regulatory proteins control their activity:
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...

