Assembly and Maintenance of Myofibrils in the Heart

The assembly of actin and myosin to the paracrystalline arrangement of myofibrils in striated muscle, that is, heart and skeletal, has puzzled many a cell biologist. Different models, based on cultured cardiomyocytes, were proposed for the last 30 years to explain the sequence of events. These were then evaluated during heart development in embryos in situ and more recently in cardiomyocytes that were derived from human induced pluripotent stem cells (iPSC-CMs). A lot of the initial work was quite descriptive but recent advances in gene editing technology and in super resolution microscopy allow a more targeted functional analysis and will give unprecedented insight. This review will discuss the general principles of myofibril assembly in the heart and cover new findings on myofibril maintenance and turnover.