The MRTFs (myocardin-releated transcription factors) protein family consists of myocardin, MRTF-A (MKL1, MAL) and MRTF-B (MKL2). These proteins are included in the common family due to the presence of evolutionarily conserved domains which are responsible for homo- and heterodimerization with other members of the family as well as actin binding and transcription activation. Despite high structural homology, these factors present different characteristics in terms of localization. The expression of myocardin is limited to the myocardial cells and smooth muscle cells, exclusively, whereas MRTF-A and MRTF-B are commonly found in various cells and tissues. These proteins interact with MADS box transcription factors as well as serum response factors (SRF) thus being engaged into signal transduction, which results from cytoskeleton reorganisation, from cytoplasm to the nucleus. It has been concluded that these proteins both take part in muscle tissue differentiation as well as mediate the development of pathological conditions (vascular diseases, cancer and fibrosis).