A Cdc42- and Rac-interactive binding (CRIB) domain mediates functions of coronin.
Proc Natl Acad Sci U S A
; 111(1): E25-33, 2014 Jan 07.
Article
in En
| MEDLINE
| ID: mdl-24347642
ABSTRACT
The Cdc42- and Rac-interactive binding motif (CRIB) of coronin binds to Rho GTPases with a preference for GDP-loaded Rac. Mutation of the Cdc42- and Rac-interactive binding motif abrogates Rac binding. This results in increased 1evels of activated Rac in coronin-deficient Dictyostelium cells (corA(-)), which impacts myosin II assembly. corA(-) cells show increased accumulation of myosin II in the cortex of growth-phase cells. Myosin II assembly is regulated by myosin heavy chain kinase-mediated phosphorylation of its tail. Kinase activity depends on the activation state of the p21-activated kinase a. The myosin II defect of corA(-) mutant is alleviated by dominant-negative p21-activated kinase a. It is rescued by wild-type coronin, whereas coronin carrying a mutated Cdc42- and Rac-interactive binding motif failed to rescue the myosin defect in corA(-) mutant cells. Ectopically expressed myosin heavy chain kinases affinity purified from corA(-) cells show reduced kinase activity. We propose that coronin through its affinity for GDP-Rac regulates the availability of GTP-Rac for activation of downstream effectors.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
4-Butyrolactone
/
Gene Expression Regulation
/
Cdc42 GTP-Binding Protein
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Rac GTP-Binding Proteins
Language:
En
Year:
2014
Type:
Article