ACTA1 and Cirrhosis: In addition, IHC of serial liver sections of patients diagnosed with cirrhosis (n = 4) showed that α-SMA-positive stroma area were also strongly positive for both pPYK2(Y402) and YAP (Fig. 7I), indicating that activated human HSCs also expressed high levels of phosphorylated PYK2 and YAP as well as α-SMA.