Protects actin filaments from depolymerization. Interacts with CTNNB1 (By similarity). Interacts with F-actin, FLNC and VASP. Colocalizes with actin stress fibers. Isoform A, isoform B and isoform C are expressed in heart. Xin repeats bind F-actin. 'Xin' means 'heart' in Chinese. Belongs to the Xin family.