Previous work conducted in the lab of Prof. Zhenguo Wu showed that Dusp27 is an important muscle protein. It belongs to the dual-specificity phosphatase (DUSPs) family due to the presence of a conserved DUSP domain, and appears to be catalytically inactive because of the substitution of a conserved cysteine to serine. Extensive in vivo studies have shown that Dusp27 plays a critical role in sarcomere assembly. However, the mechanism underlying the critical role of Dusp27 in sarcomere assembly remains to be elucidated.

In this study, yeast two hybrid was conducted to screen for the interacting proteins of Dusp27, which may help to elucidate its functional role. 92 different genes were finally identified, and a large portion of these were sarcomeric proteins. Based on the result...[ Read more ]

Previous work conducted in the lab of Prof. Zhenguo Wu showed that Dusp27 is an important muscle protein. It belongs to the dual-specificity phosphatase (DUSPs) family due to the presence of a conserved DUSP domain, and appears to be catalytically inactive because of the substitution of a conserved cysteine to serine. Extensive in vivo studies have shown that Dusp27 plays a critical role in sarcomere assembly. However, the mechanism underlying the critical role of Dusp27 in sarcomere assembly remains to be elucidated.

In this study, yeast two hybrid was conducted to screen for the interacting proteins of Dusp27, which may help to elucidate its functional role. 92 different genes were finally identified, and a large portion of these were sarcomeric proteins. Based on the result, some sarcomeric proteins, such as Filamin C, Myotilin, TroponinT1, TroponinI2, were confirmed to interact with Dusp27 in 293 cell systems. In addition, Mass Spectrometry was performed to identify more candidates which associate with Dusp27. Muscle tissue lysate from WT and Dusp27 muscle specific conditional KO mice were used to conduct endogenous immunoprecipitation with Dusp27 antibody and then the precipitated complex were subject to mass spectrometry analysis. The results indicated that several sarcomeric proteins, including TroponinT, Troponin I, Myotilin and Tropomyosin, could potentially interact with Dusp27 in vivo.

To determine whether the inactive catalytic domain of Dusp27 mediates the interactions with other proteins, two truncated constructs of Dusp27 were used in yeast two hybrid assays, one is from 74 to 295 amino acids, containing the catalytic domain and the other is from 296 to 520 amino acids. As a result, Myotilin and Filamin C might interact with the inactive DUSPc domain, while TroponinI2 and TroponinT3 do not.