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

Abstract

Summary This research aimed to investigate the influence of myosin regulatory light chain (MRLC) phosphorylation on actomyosin dissociation and myosin degradation in post‐mortem ovine longissimus thoracis (LT) muscle with a purpose for strategies to improve meat quality in practice. Data obtained show that the highest actomyosin dissociation occurred at 48 h post‐mortem. Based on the cluster analysis of the actomyosin dissociation degree at 48 h post‐mortem, samples were divided into high, middle and low‐actomyosin dissociation groups. During 0.5–72 h post‐mortem, the phosphorylation level of MRLC significantly decreased (P < 0.05), while actomyosin dissociation, and degradation of MRLC and myosin heavy chains (MHC) significantly increased (P < 0.05). The level of MRLC phosphorylation was negatively correlated with the degree of actomyosin dissociation (r = −0.794, P < 0.05), and the degradation of MRLC (r = −0.764, P < 0.05) and MHC (r = −0.826, P < 0.05). In conclusion, phosphorylation of MRLC may regulate actomyosin dissociation, as well as degradation of MRLC and MHC.

Measuring quantitative proteomic distance between Spanish beef breeds

“…MYLPF is a phosphoprotein with levels of phosphorylation modulated by the concerted action of Ca2+/calmodulin-dependent skeletal muscle myosin light chain kinase and protein phosphatase type 1 activities (Stull, Kamm, & Vandenboom, 2011). A number of studies in bovine, ovine and porcine have shown that changes in MYLPF phosphorylation levels are related to phenomena with impact in meat tenderness such as the skeletal muscle contraction force of fast-twitch fibers type IIb, the progress of rigor mortis, the response to pre-slaughter stress, actomyosin dissociation and myosin degradation (Muroya, Ohnishi-Kameyama, Oe, Nakajima, Shibata, & Chikuni, 2007;Franco et al, 2015;Chen et al, 2016;Lana & Zolla, 2016;Cao, Hou, Shen, Zhang, & Wang, 2019;Mato et al, 2019). In addition, we found that MYLPF is the single protein interacting with all partners (i.e.…”

Effects of protein posttranslational modifications on meat quality: A review

“…Gao, Li, Li, Du, and Zhang (2017) established an in vitro model through adding alkaline phosphatase and phosphatase inhibitor and reported that phosphorylation of myosin regulatory light chain in lamb positively regulated actomyosin dissociation during incubation at 4 °C, which benefited meat tenderness. Cao, Hou, Shen, Zhang, and Wang (2019) divided lamb samples into three groups of different actomyosin dissociation degrees according to the content of liberated actin in postslaughter sheep muscle and the results demonstrated that the phosphorylation of myosin regulatory light chain in lamb negatively regulated actomyosin dissociation. It is possible that other specific but not nonspecific phosphatase or protein kinase exist in postmortem muscle that phosphorylate certain sites of myosin regulatory light chain.…”