HSP90AA1 and Myocardial fibrosis: Furthermore, Hsp90ab1 and Hsp90aa1 isoforms are involved in the formation of the cell surface TGF βRI complex, and this complex increases the production of collagen in TGF β-activated fibroblasts, suggesting that the inhibition of Hsp90 could reduce myocardial fibrosis (Garcia et al., 2016).