Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.


Sci. STKE, 3 July 2001
Vol. 2001, Issue 89, p. tw6
[DOI: 10.1126/stke.2001.89.tw6]

EDITORS' CHOICE

Cell Biology Calcium Signals Stop Through CAPRI

Lockyer et al. have identified and characterized a new member of the Ras guanosine triphosphatase (GTPase)-activating protein (GAP) family that is regulated by calcium and thus, named Ca2+-promoted Ras activator (CAPRI). Capri has structural similarity (a pleckstrin homology domain, a GAP-related domain, and a Bruton's tyrosine kinase motif) to members of the Ras GAP1 subfamily, but unlike other members of the subfamily, CAPRI has functional calcium-binding C2 domains. The redistribution of CAPRI to the plasma membrane in transfected cells was stimulated by increases in intracellular Ca2+ (either by treatment with a calcium ionophore or activation of the purinergic G protein-coupled receptor that activates phospholipase C leading to increased intracellular Ca2+ owing to production of inositol trisphosphate). Unlike other members of the GAP1 family, CAPRI was not sensitive to changes in phosphatidylinositol lipids in the membrane. Increases in intracellular Ca2+ were required to activate the GAP activity of CAPRI. In transfected cells, activation of CAPRI attenuated calcium-induced activation of the Ras-mitogen-activated protein kinase (MAPK) pathway. Expression of a dominant negative form of CAPRI enhanced phosphorylation of the MAPKs ERK1 and ERK2. Thus, CAPRI may be an off switch that helps to regulate the output of calcium-mediated activation of the Ras-MAPK pathway.

P. J. Lockyer, S. Kupzig, P. J. Cullen, CAPRI regulates the Ca2+-dependent inactivation of the Ras-MAPK pathway. Current Biol. 11, 981-986 (2001). [Full Text]

Citation: Calcium Signals Stop Through CAPRI. Sci. STKE 2001, tw6 (2001).


To Advertise     Find Products


Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882