Moen Rebecca J, Cornea Sinziana, Oseid Daniel E, Binder Benjamin P, Klein Jennifer C, Thomas David D
Department of Chemistry and Geology, Minnesota State University, Mankato, MN 56001, United States.
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States.
Biochem Biophys Res Commun. 2014 Oct 24;453(3):345-9. doi: 10.1016/j.bbrc.2014.09.072. Epub 2014 Sep 26.
We have examined the chemical and functional reversibility of oxidative modification in myosin. Redox regulation has emerged as a crucial modulator of protein function, with particular relevance to aging. We previously identified a single methionine residue in Dictyostelium discoideum (Dicty) myosin II (M394, near the myosin cardiomyopathy loop in the actin-binding interface) that is functionally sensitive to oxidation. We now show that oxidation of M394 is reversible by methionine sulfoxide reductase (Msr), restoring actin-activated ATPase activity. Sequence alignment reveals that M394 of Dicty myosin II is a cysteine residue in all human isoforms of skeletal and cardiac myosin. Using Dicty myosin II as a model for site-specific redox sensitivity of this Cys residue, the M394C mutant can be glutathionylated in vitro, resulting in reversible inhibition of actin-activated ATPase activity, with effects similar to those of methionine oxidation at this site. This work illustrates the potential for myosin to function as a redox sensor in both non-muscle and muscle cells, modulating motility/contractility in response to oxidative stress.
我们研究了肌球蛋白氧化修饰的化学和功能可逆性。氧化还原调节已成为蛋白质功能的关键调节因子，与衰老尤其相关。我们之前在盘基网柄菌（Dicty）肌球蛋白II中鉴定出一个甲硫氨酸残基（M394，位于肌动蛋白结合界面的肌球蛋白心肌病环附近），其功能对氧化敏感。我们现在表明，M394的氧化可被甲硫氨酸亚砜还原酶（Msr）逆转，恢复肌动蛋白激活的ATP酶活性。序列比对显示，Dicty肌球蛋白II的M394在所有人类骨骼肌和心肌肌球蛋白同工型中是一个半胱氨酸残基。以Dicty肌球蛋白II作为该半胱氨酸残基位点特异性氧化还原敏感性的模型，M394C突变体在体外可被谷胱甘肽化，导致肌动蛋白激活的ATP酶活性可逆性抑制，其效应与该位点甲硫氨酸氧化的效应相似。这项工作说明了肌球蛋白在非肌肉和肌肉细胞中作为氧化还原传感器发挥作用的潜力，可响应氧化应激调节运动性/收缩性。
