T-tubules are complex tubular network formed by invagination of the surface membrane in cardiomyoctes.Most of the main ion channels involved in excitation-contraction coupling are concentrated at the T-tubules.They can propagate depolarization into the interior of the cell and serve to spatially and temporally synchronize Ca2+ release across the cell.Many proteins on T-tubules are tethered to actin network via actinbinding protein, which helps to stablize T-tubules system.Untill now, however, an understanding of how actin affects T-tubule formation and stablization remained elusive.We found that cytochalasin D can inhibited the loss of T-tubules in culture, which was consistent with previous report.