Protects actin filaments from depolymerization (By similarity). Involved in cardiac morphogenesis. Interacts with F-actin, FLNC and VASP. Colocalizes with actin stress fibers. First expressed at stage 8 in the paired lateral plate mesoderm that forms the primordia of the heart. At stages 10 and 11, expressed in the lateral regions of the developing heart tube. At stage 13, strongly expressed in the right side of the looping heart. At stage 15, expressed in rostral somites. At stage 20, expressed in heart, skeletal muscle and tongue. Xin repeats bind F-actin. Belongs to the Xin family.