Dephosphorylation of myosin regulatory light chain modulates actin–myosin interaction adverse to meat tenderness

Abstract

The objective of this study was to investigate the relationship between the dephosphorylation of myosin regulatory light chain and actin-myosin interaction after muscle homogenate was treated with alkaline phosphatase and phosphatase inhibitor. The myosin regulatory light chain was significantly dephosphorylated by alkaline phosphatase after incubation. Among different groups, dephosphorylated myosin regulatory light chain to a much greater extent leads to a lower actomyosin dissociation degree, thereby raising the actomyosin ATPase activity, whereas it exhibits a higher actomyosin dissociation degree and a lower actomyosin ATPase activity when the myosin regulatory light chain was in a low dephosphorylated state. The data suggest that the dephosphorylation of myosin regulatory light chain modulates actomyosin dissociation (the number of myosin interact with actin) negatively and has a positive influence on actomyosin ATPase activity (the interacting force between myosin and actin).Dephosphorylation modulates actinmyosin X. Gao et al.

Proteome changes in lamb semimembranosus muscles associated with the inclusion of sunflower cake in their diet

“…In skeletal muscle, the most abundant myofibrillar proteins are actin and myosin, which forms thick and thin filaments. A key step in ageing meat is the weakening of the actomyosin interaction, which causes changes in meat texture (Gao et al, 2017). In addition, tropomyosin and troponin, which form complexes with F-actin filaments, are also involved in muscle contraction; hence, these structural proteins are closely associated with tenderness.…”

Effects of temperature on protein phosphorylation in postmortem muscle

“…Currently, multiple posttranslational modifications in postmortem muscle, such as phosphorylation, ubiquitylation, acetylation, methylation and alkylation, are considered. Protein phosphorylation has been especially extensively studied with regard to meat quality …”

“…Phosphorylation alters the proteolytic susceptibility of myofibrillar proteins and prevents myofibrillar protein degradation by μ‐calpain . Gao et al . suggested that dephosphorylation of myosin regulatory light chain alters the actomyosin dissociation and thus meat tenderness.…”

“…Protein phosphorylation has been especially extensively studied with regard to meat quality. [7][8][9][10][11] A number of phosphorylated proteins have been identified in postmortem muscles with variable tenderness, colour stability, pH decline rate or genotype. [12][13][14][15] These studies have uncovered certain pathways or mechanisms of regulation of meat quality by protein phosphorylation.…”

Phosphorylation of myosin regulatory light chain affects actomyosin dissociation and myosin degradation

“…Reversible protein phosphorylation catalysed by protein phosphatases and protein kinases alters protein structure and function, including protein-protein interactions and protein biological activity (Murray & Steck, 1984;Chu & Silverstein, 2012). Previous studies have revealed that phosphorylation of myofibrillar proteins may affect actomyosin dissociation through muscle contraction (Chen et al, 2016), especially the phosphorylation of myosin regulatory light chain (MRLC) (Gao et al, 2017). Phosphorylation of MRLC was first discovered in rabbit skeletal muscle and then in the myocardium (Perrie & Perry, 1970;Perrie et al, 1973;Frearson & Perry, 1975).…”