Calpastatin inhibits the activity of phosphorylated μ-calpain in vitro. (15th February 2019)

• Record Type: Journal Article
• Authors: Du, Manting; Li, Xin; Li, Zheng; Shen, Qingwu; Ren, Chi; Zhang, Dequan
• Is Part Of: Food chemistry. Volume 274(2019)
• Page Start: 743
• Page End: 749
• Publication Date: 2019-02-15
• Subjects: Calpastatin -- μ-Calpain -- Phosphorylation -- Protein kinase A -- Alkaline phosphatase; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2018.09.073
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Dephosphorylation and PKA phosphorylation of μ-calpain promotes it activation. The degradation of PKA phosphorylated μ-calpain decreased by calpastatin. Calpastatin presents greater inhibition to PKA phosphorylated μ-calpain. Abstract: The objective of this study was to investigate the effect of phosphorylation on the sensitivity of μ-calpain to the inhibition induced by calpastatin. Purified μ-calpain was incubated with alkaline phosphatase (AP) or protein kinase A (PKA) to modulate the phosphorylation level of μ-calpain. Accurately 25, 50, 100 and 150 units of AP/PKA-treated μ-calpain were mixed with the same amounts of heat stable proteins and incubated at 4 °C. In the calpastatin-free system, AP and PKA-treated μ-calpain had higher proteolytic activity compared to the control. Intact AP-treated μ-calpain degraded fastest in the 50, 100 and 150 unit μ-calpain incubation systems. However, the degradation rate of μ-calpain in control and PKA group was non-significant in 100 and 150 unit μ-calpain systems. Our results demonstrated that, compared to dephosphorylated and control μ-calpain, calpastatin presents greater inhibition to PKA phosphorylated μ-calpain. This study increases understanding of the mechanism of μ-calpain activity regulated by phosphorylation.