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Regulation of activation of Rac1 and Cdc42 GTPases in CHRF‐288‐11 cells
Author(s) -
Bhullar Rajinder Pal,
Xu Bing
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.769.1
Subject(s) - rac1 , thrombin , cdc42 , microbiology and biotechnology , calmodulin , chemistry , gtpase , biology , platelet , biochemistry , immunology , signal transduction , enzyme
Rac1 and Cdc42 are members of the Rho family of small GTPases and have been shown to promote the formation of lamellipodia and filopodia at the leading edge of motile cells and thus affect cell migration. In the current study we have investigated the activation of Rac1 and Cdc42 by thrombin or collagen in the megakaryocytic cell line, CHRF‐288‐11. Maximal activation of Rac1 by thrombin or collagen was observed at 3 min and 1 min respectively. Similar results were obtained for the thrombin or collagen mediated activation of Cdc42. The calmodulin specific inhibitor, W7, abolished the thrombin or collagen mediated activation of Rac1 in CHRF‐288‐11 cells. However, W7 had no effect on the activation of Cdc42 by thrombin or collagen. The less potent calmodulin inhibitor, W5, did not have any effect on Rac1 or Cdc42 activation by thrombin or collagen. Transient over‐expression of calmodulin in CHRF‐288‐11 cells increased the basal and thrombin mediated activation of Rac1 when compared to control but had no effect on the basal and thrombin mediated activation of Cdc42 when compared to control. The results demonstrate a role for calmodulin in the activation step of Rac1 in CHRF‐288‐11 cells. This is similar to the results for Rac1 regulation in platelets and suggests that the CHRF cells can serve as a model for platelets. This work was supported by a grant to RPB from the Heart & Stroke Foundation of Manitoba.