HSP70 drives myoblast fusion during C2C12 myogenic differentiation.

In response to injury, skeletal muscle stem cells (MuSCs) undergo myogenesis where they become activated, proliferate rapidly, differentiate and undergo fusion to form multinucleated myotubes. Dramatic changes in cell size, shape, metabolism and motility occur during myogenesis, which cause cellular stress and alter proteostasis. The molecular chaperone heat shock protein 70 (HSP70) maintains proteostasis by regulating protein biosynthesis and folding, facilitating transport of polypeptides across intracellular membranes and preventing stress-induced protein unfolding/aggregation.

Expression and localization of heat-shock proteins during skeletal muscle cell proliferation and differentiation and the impact of heat stress.

Skeletal myogenesis is a coordinated sequence of events associated with dramatic changes in cell morphology, motility, and metabolism, which causes cellular stress and alters proteostasis. Chaperones, such as heat-shock proteins (HSPs), play important roles in limiting cellular stresses and maintaining proteostasis, but whether HSPs are specifically involved in myogenesis is not well understood. Here, we characterized gene and protein expression and subcellular localization of various HSPs in proliferating C2C12 myoblasts and differentiating myotubes under control conditions and in response to heat stress.