Phosphorylation of Calpastatin Negatively Regulates the Activity of Calpain
Yuqiang Bai,
Chengli Hou,
Caiyan Huang,
Fei Fang,
Yu Dong,
Xin Li,
Dequan Zhang
Affiliations
Yuqiang Bai
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Quality & Safety in Harvest, Storage, Transportation, Management and Control, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Chengli Hou
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Quality & Safety in Harvest, Storage, Transportation, Management and Control, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Caiyan Huang
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Quality & Safety in Harvest, Storage, Transportation, Management and Control, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Fei Fang
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Quality & Safety in Harvest, Storage, Transportation, Management and Control, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Yu Dong
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Quality & Safety in Harvest, Storage, Transportation, Management and Control, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Xin Li
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Quality & Safety in Harvest, Storage, Transportation, Management and Control, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Dequan Zhang
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products Quality & Safety in Harvest, Storage, Transportation, Management and Control, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Tenderness is an important characteristic of meat quality. Calpastatin and calpain play important roles in meat tenderization. However, it is not clear how phosphorylation affects the regulation of calpastatin on μ-calpain and, consequently, meat tenderness. Calpastatin with high and low phosphorylation levels were obtained in vitro corresponding to the treatments by protein kinase A (PKA) and alkaline phosphatase. Then, calpain was incubated with calpastatin with different phosphorylation levels, and the effect of calpastatin on calpain activity under different phosphorylation levels was analyzed. The results showed that PKA promoted the phosphorylation of calpastatin, and a high phosphorylation level was maintained during incubation. The degradation rate of μ-calpain in AP group was higher than that in the other groups, meaning there was lower inhibition of calpastatin on calpain activity. The degradation of calpastatin was lower and its structure was more stable after phosphorylation. One more serine 133 site of calpastatin was identified in PKA group compared with the other groups. Phosphorylation at serine 133 of calpastatin enhanced its inhibition on calpain activity by maintaining its structural stability, thus inhibiting the tenderization of meat.
