IQGAP2 cellular localization.

(A-F) COS1 cells transfected with the IQGAP2 cDNA were fixed and permeabilized, followed by confocal microscopic detection of F-actin (B,E) or IQGAP2 (A,D). The overlay images (C,F) demonstrate colocalization (yellow) readily observed in the lamellipodia (A,C arrows) or filopodia (D,F arrows). Note that the IQGAP2/actin colocalization pattern reflects that expected for rac1/cdc42-mediated filopodial/lamellipodial structures. (G-I) Platelets activated by cytocentrifugation onto glass slides were stained with the anti-IQGAP2 mAb (H), with the corresponding phase-contrast image displayed in panel G and the phase/overlay image in panel I. Note that IQGAP2 expression is essentially restricted to platelet filopodial extensions (FE), to the exclusion of the platelet contractile bodies (CB). (J-L) Unactivated platelets (J) or thrombin-activated platelets (K,L) were stained with anti-IQGAP2 mAb after fixation and permeabilization. Note the redistribution of IQGAP2 within the platelet cytoskeleton in thrombin-stimulated platelets (panel L is a higher magnification of the boxed platelet in panel K); identical results were seen using PAR1^42-47-stimulated platelets (not shown). Scale bars for corresponding COS1 or platelet immunofluorescence staining are shown.