%0 Journal Article
%T Cytoskeleton and Adhesion in Myogenesis
%A Manoel Lu¨ªs Costa
%J ISRN Developmental Biology
%D 2014
%R 10.1155/2014/713631
%X The function of muscle is to contract, which means to exert force on a substrate. The adaptations required for skeletal muscle differentiation, from a prototypic cell, involve specialization of housekeeping cytoskeletal contracting and supporting systems into crystalline arrays of proteins. Here I discuss the changes that all three cytoskeletal systems (microfilaments, intermediate filaments, and microtubules) undergo through myogenesis. I also discuss their interaction, through the membrane, to extracellular matrix and to other cells, where force will be exerted during contraction. The three cytoskeletal systems are necessary for the muscle cell and must exert complementary roles in the cell. Muscle is a responsive system, where structure and function are integrated: the structural adaptations it undergoes depend on force production. In this way, the muscle cytoskeleton is a portrait of its physiology. I review the cytoskeletal proteins and structures involved in muscle function and focus particularly on their role in myogenesis, the process by which this incredible muscle machine is made. Although the focus is on skeletal muscle, some of the discussion is applicable to cardiac and smooth muscle. 1. Introduction: Myogenesis When a muscle contracts it can shorten or develop force. To accomplish its physiological role of moving us around, it must do both¡ªand for this, muscle cells undergo a dramatic structural and physiological change during development, from a single cell 20£¿¦Ìm long into a multinucleated muscle fiber 30£¿cm in length. The contractile apparatus itself is based on cytoskeletal structures that exist in all cells and includes microfilaments and intermediate filaments. In striated muscle, these filaments are organized in a crystalline fashion and contract synchronously after a nerve impulse. Moreover, all the cytoskeletal components, including microtubules, have to change during myogenesis to accommodate the physiological muscular adaptation. Since muscle needs a substrate to develop tension, important adaptations in cell adhesion also occur during muscle differentiation. In order to contextualize the review, it is convenient to define the major steps in myogenesis as determination and differentiation (Figure 1). Skeletal muscle determination begins with molecules secreted from the neural tube and notochord, such as wingless (Wnt) and sonic hedgehog (Shh) [1]. These molecules in turn induce the expression of muscle regulatory genes such as myoD and myf, which control all the features of the muscle differentiation program, including cell cycle
%U http://www.hindawi.com/journals/isrn.developmental.biology/2014/713631/