International Journal of Molecular Sciences Review MRTF: Basic Biology and Role in Kidney Disease Maria Zena Miranda 1, Zsuzsanna Lichner 1, Katalin Szászi 1,2 and András Kapus 1,2,3,* 1 Keenan Research Centre for Biomedical Science of the St. Michael’s Hospital, Toronto, ON M5B 1W8, Canada;
[email protected] (M.Z.M.);
[email protected] (Z.L.);
[email protected] (K.S.) 2 Department of Surgery, University of Toronto, Toronto, ON M5T 1P5, Canada 3 Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada * Correspondence:
[email protected] Abstract: A lesser known but crucially important downstream effect of Rho family GTPases is the regulation of gene expression. This major role is mediated via the cytoskeleton, the organization of which dictates the nucleocytoplasmic shuttling of a set of transcription factors. Central among these is myocardin-related transcription factor (MRTF), which upon actin polymerization translocates to the nucleus and binds to its cognate partner, serum response factor (SRF). The MRTF/SRF complex then drives a large cohort of genes involved in cytoskeleton remodeling, contractility, extracellular matrix organization and many other processes. Accordingly, MRTF, activated by a variety of mechanical and chemical stimuli, affects a plethora of functions with physiological and pathological relevance. These include cell motility, development, metabolism and thus metastasis formation, inflammatory responses and—predominantly-organ fibrosis. The aim of this review is twofold: to provide an up- to-date summary about the basic biology and regulation of this versatile transcriptional coactivator; and to highlight its principal involvement in the pathobiology of kidney disease.