FIGURE 6.

Myocardin-like transcription factors regulate smooth muscle phenotype. Understanding of the regulation of smooth muscle phenotype was advanced significantly by the discovery that the coactivator myocardin participates in the activation of transcription for a majority of genes that code for contractile proteins in smooth muscle.⁵⁴ This discovery brought together the roles of ternary complex factor, serum response factor, and myocardin in a hierarchy that was consistent with known patterns of smooth muscle phenotype control obtained from studies of wound repair, atherosclerosis, tumor vasculogenesis, and Alzheimer disease. The discovery of myocardin has thus helped unify these fields and stimulated many new insights into how both physiological and pathologic stimuli influence smooth muscle differentiation. For details, please see.^52,53