Early Stage Morphogenesis of Transverse Tubules in Rat Cardiomyocytes: The Role of pBIN1

TTs start to develop as budding tubules branching from membrane hubs around Z-discs. This process depends at least partially on the tubulation function of pBIN1 (BIN1 isoforms with PIBM [Bin1+11 and Bin1+11+17]), which is constitutively expressed in rat and human cardiomyocytes. Defective TT morphogenesis due to altered BIN1 splicing in cardiomyocytes may have potential implications in heart diseases.