Neuregulin-1β treatment induces phosphorylation of ErbB2 receptor in human cardiac fibroblasts. A, Western blot analysis of protein lysates of NHCV fibroblasts treated for 30 min with 30 ng/mL of NRG-1β. Bands shown are 185 kDa and were detected using an anti-rabbit antibodies that recognize phosphorylated ErbB2 (pErbB2) at tyrosine position 1289 (Tyr1248) and pan ErbB2. A representative blot is shown. B, Western blot analysis of protein lysates of NHCV fibroblasts treated for 30 min with 30 ng/mL of NRG-1β. Bands shown are 185 kDa and were detected using anti-rabbit antibodies that recognize phosphorylated ErbB2 (pErbB2) at tyrosine positions 1221 and 1222 (Tyr1221/1222), and pan ErbB2. C, Graphical representation showing densitometry analysis result for blots shown in A and B. Asterisks represent significance (n= 3, *p < 0.05 for NRG-1β-treated cells compared to controls).