Figure 11. Increased phosphorylation of MLC2v in young adult dysferlin‐deficient mouse hearts .

A, representative Pro‐Q‐stained gel of total protein extracts from isolated working mouse hearts treated with 10 nm isoproterenol and densitometry quantification showed a 52.10±4.1% higher phosphorylation of MLC2v in dysferlin knockout hearts as compared with wild‐type controls (*P<0.05 in Student's t test). Phosphorylation of cardiac TnT and cardiac TnI was not different in the two groups. Pro‐Q diamond stain detected a trend of increase in the phosphorylation of MyBP‐C in dysferlin knockout hearts (40.16±12.61% higher than wild‐type control, P = 0.093 in two‐tailed Student's t test). Western blot further showed a similar trend of increased MyBP‐C phosphorylation at Ser₂₈₂ (37.47±12.36% higher than wild‐type control, P = 0.060 in two‐tailed Student's t test). B, representative Pro‐Q‐stained gel of rapidly isolated cardiac muscle and densitometry analysis confirmed the increased phosphorylation of MLC2v in dysferlin knockout mouse hearts in vivo as compared with that in wild‐type mice (increased by 58.42±5.28% in left ventricle and 54.16±2.72% in right ventricle). In contrast to ex vivo working hearts treated with 10 nm isoproterenol, dysferlin knockout mouse hearts rapidly isolated under anaesthesia did not show the trend of in vivo increases in MyBP‐C phosphorylation. C, representative Western blot of urea‐glycerol‐PAGE gel and densitometry analysis confirmedthe increased phosphorylation of MLC2v in dysferlin knockout mouse working hearts treated with 10 nm isoproterenol (44.43±0.18% of total MLC2v vs. 35.19±2.20% in wild‐type control hearts). *P<0.05 in Student's t‐test.