In:
American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 285, No. 4 ( 2003-10), p. C797-C805
Abstract:
Platelets transform from disks to irregular spheres, grow filopodia, form ruffles, and spread on surfaces coated with anti-FcγRIIA antibody. FcγRIIA cross-linking leads to a tenfold increase in actin filament barbed end exposure and robust actin assembly. Activation of the small GTPases Rac and Cdc42 follows FcγRIIA cross-linking. Shape change, actin filament barbed end exposure, and quantifiable actin assembly require phosphoinositide 3-kinase (PI3-kinase) activity and a rise in intracellular calcium. PI3-kinase inhibition blocks activation of Rac, but not of Cdc42, and diminishes the association of Arp2/3 complex and CapZ with polymerized actin. Furthermore, addition of constitutively active D-3 phosphorylated polyphosphoinositides or recombinant PI3-kinase subunits to octylglucoside-permeabilized platelets elicits actin filament barbed end exposure by releasing gelsolin and CapZ from the cytoskeleton. Our findings place PI3-kinase activity upstream of Rac, gelsolin, and Arp2/3 complex activation induced by FcγRIIA and clearly distinguish the FcγRIIA signaling pathway to actin filament assembly from the thrombin receptor protease-activated receptor (PAR)-1 pathway.
Type of Medium:
Online Resource
ISSN:
0363-6143
,
1522-1563
DOI:
10.1152/ajpcell.00165.2003
Language:
English
Publisher:
American Physiological Society
Publication Date:
2003
detail.hit.zdb_id:
1477334-X
SSG:
12
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