Calcineurin signaling and neural control of skeletal muscle fiber type and size.

Nerve activity controls muscle contractile function and muscle gene expression. Although excitation-contraction coupling is well characterized, excitation-transcription coupling is still poorly understood. Pharmacological and genetic approaches have been used to dissect the signaling pathways that mediate the effect of nerve activity on muscle fiber type and size. In particular, the role of calcineurin has recently been the subject of intensive investigation and debate. The identification of the transduction pathways involved in neuromuscular signaling has implications for the development of new therapeutic strategies to prevent muscle wasting and loss of muscle power resulting from aging, disuse and neuromuscular disorders.