ACTA1 and atherosclerosis: There is, however, an important caveat to these observations; while the induction of contractile marker proteins (such as αSMA and SM22α) by TGFβ can be viewed as atheroprotective in SMCs, very recent studies investigating the origin of αSMA+ cells within atherosclerotic lesions have demonstrated that activation of this transcriptional programme by TGFβ in endothelial cells (ECs) can instead promote the induction of atherosclerosis.