Desmin Filaments Influence Myofilament Spacing and Lateral Compliance of Slow Skeletal Muscle Fibers

INTRODUCTION

Desmin is an abundant cytoskeletal protein in skeletal muscle, forming intermediate filaments concentrated at the Z-disks of the sarcomeres. The intermediate filaments couple sarcomeres in the lateral direction and form connections to the nucleus and to the costameres at the sarcolemma (Lazarides et al., 1982). Desmin filaments are also found in the neuromuscular and myotendinous junctions (Askanas et al., 1990; Tidball, 1992). In cardiac muscle, desmin is associated with the intercalated discs and is highly expressed in the Purkinje fibers (Thornell and Eriksson, 1981). In smooth muscle, desmin is located in the cytoskeletal region at the dense bodies and dense plaques (Bond and Somlyo, 1982; Small and Sobieszek, 1977).