Fig. 7

Truncated JMY variants and isolated JMY-V/VVVCA domains induce MRTF-SRF activity despite inhibited actin polymerization. MRTF-SRF activation by various JMY constructs was analyzed in serum-starved NIH 3 T3 cells following Arp2/3 inhibition or treatment with latrunculin B (LatB). a, b: Induced SRF reporter activity in myc-JMY overexpressing cells upon siRNA-mediated Arp3 knockdown (a) or treatment with 100 μM CK-666 for 7 h (b). As control, cells were stimulated with 15% serum for 7 h (FCS). c: Validation of Arp3 inhibition by immunofluorescence staining for endogenous Arp3 (red) and F-actin (Atto 488 phalloidin) (green). d, e: Significant induction of MRTF-SRF in JMY mutant (d) and JMY-V/VVVCA (e) cells following inhibited actin polymerization by LatB (0.5–1 μM, 7.5 h). All data were normalized to the starvation control which is set to 1. Error bars, s.e.m., n ≥ 3 (* p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001 according to an unpaired one sample student’s t-test)