DUSP5 and cardiomyopathy: In addition, we identified up-regulation of dual specificity phosphatase 4 (DUSP4) and DUSP5 in 1-month Lmna−/− mice, while only DUSP4 was up-regulated in mice with LmnaH222P/H222P-induced cardiomyopathy based on the study by Worman et al. 17.