Kif5b controls the localization of myofibril components for their assembly and linkage to the myotendinous junctions

• DOI: 10.1242/dev.085969
• Publication Date: 2013-01-04T23:06:55Z
• Authors: Zai Wang; Ju Cui; Wai Man Wong; Xiuling Li; Wenqian Xue; Raozhou Lin; Jing Wang; Peigang Wang; Julian A. Tanner; Kathryn S. E. Cheah; Wutian Wu; Jian-Dong Huang
• Keywords: Mice, Knockout; 0301 basic medicine; Myoblasts, Skeletal; Green Fluorescent Proteins; Gene Expression Regulation, Developmental; Golgi Apparatus; Kinesins; Cell Differentiation; Nerve Tissue Proteins; Muscular Dystrophy, Animal; Muscle Development; Desmin; Hindlimb; Mitochondria; Actin Cytoskeleton; Mice; 03 medical and health sciences; Intercellular Junctions; Intermediate Filament Proteins; Myofibrils; Animals; Muscle, Skeletal

Controlled delivery of myofibril components to the appropriate sites of assembly is crucial for myofibrillogenesis. Here, we show that kinesin-1 heavy chain Kif5b plays important roles in anterograde transport of α-sarcomeric actin, non-muscle myosin IIB, together with intermediate filament proteins desmin and nestin to the growing tips of the elongating myotubes. Mice with Kif5b conditionally knocked out in myogenic cells showed aggregation of actin filaments and intermediate filament proteins in the differentiating skeletal muscle cells, which further affected myofibril assembly and their linkage to the myotendinous junctions. The expression of Kif5b in mutant myotubes rescued the localization of the affected proteins. Functional mapping of Kif5b revealed a 64-amino acid α-helix domain in the tail region, which directly interacted with desmin and might be responsible for the transportation of these proteins in a complex.