CRAG mediates c-Fos-dependent AP-1 activation via SRF. A, CRAG activates SRF. G3, centaurin-γ3; G2-s, centaurin-γ2 short form. B, identification of CRAG domains required for SRF activation. WT, CRAG WT; ΔC, CRAGΔC 1–374 mutant; NLSm, CRAG NLS mutant K386E R369E; ΔN, CRAGΔN 60–375 mutant; GTPm, CRAG GTPase mutant. C, inhibitory effects of two SRF mutants and SRF cofactor MAL mutant on CRAG-induced SRF activation. D, effects of SRF inhibitions on CRAG-induced AP1 activities. (C–E) SRF cofactor MAL mutant (C471) and two SRF mutants (Δ413 and Δ338) are described under “Experimental Procedures.” A–D, Neuro2A cells were transfected with both pSRF-Luc and pRL-CMV together with either empty vector or the indicated vector. Luciferase activities were assessed 48 h after the transfection. Error bars indicate ±S.D. (n = 3). *, p < 0.05; **, p < 0.01; ***, p < 0.005 (Student's t test). E, effects of SRF inhibitions on CRAG-induced c-Fos activations. Lysates of Neuro2A cells as described above were immunoblotted with the indicated antibodies.