Acts as an activator of serum response factor (SRF)-dependent transcription possibly by inducing nuclear translocation of MKL1 or MKL2 and through a mechanism requiring Rho-actin signaling. Binds F-actin and ABLIM1, ABLIM2 AND ABLIM3. Interaction with ABLIM2 AND ABLIM3 enhances activity (By similarity). Localized to the I-band of the sarcomere and to a lesser extent to the sarcomeric structure between Z-lines. Predominantly expressed in heart and skeletal muscle, and expressed at lower levels in adrenal gland, brain, kidney, liver, and testis. Expressed in the left ventricle of embryonic heart and is postnatally up-regulated through to adulthood. Up-regulated within 1 hour in the left ventricle following the application of pressure overload by aortic banding. The actin-binding domain 1 (ABD1) is intrinsically disordered, and binds to F-actin with higher affinity than ABD2.