Actin Binding Rho Activating Protein (ABRA)

STARS directly associates with actin. Deletion mutant experiments revealed that STARS requires 2 separate but codependent regions (amino acids 234-279 and 346-375) to bind to actin. STARS localized to the I-band of the sarcomere in rat primary cardiomyocytes and to actin stress fibers in transfected cells. In situ hybridization experiments showed that STARS was expressed specifically in the primitive heart tube of mice at embryonic day 8.75 and also in skeletal muscle by E10.5.the conserved C-terminal region of STARS was necessary and sufficient to stimulate expression from the SM22 promoter, which contains 2 serum response factor (SRF)-binding sites (CArG boxes).the transcriptional activation by STARS is mediated in large part by the cytoskeleton but also by a Rho-dependent mechanism.