Protects actin filaments from depolymerization. Interacts with FLNC and VASP (By similarity). Interacts with F-actin and CTNNB1. Colocalizes with actin stress fibers. Expressed in heart and skeletal muscle. In heart, present in intercalated disks (at protein level). At 8 dpc, expression is restricted to cardiogenic cells. At 10 dpc, expressed in heart and rostral somites. At 13.5 dpc, expressed in heart and skeletal muscle (at protein level). Xin repeats bind F-actin. Mice are predisposed to hypertrophic cardiomyopathy, and display abnormal cardiac electrophysiological characteristics, including defects in atrial depolarization and ventricular repolarization. Belongs to the Xin family.