Vigoreaux J O, Perry L M
Department of Zoology, University of Vermont, Burlington 05405.
J Muscle Res Cell Motil. 1994 Dec;15(6):607-16. doi: 10.1007/BF00121068.
Drosophila stretch-activated flight muscles contain flightin, a novel myofibrillar protein that interacts with myosin filaments. We have identified eleven flightin isoelectric variants that can be subdivided into phosphorylated and non-phosphorylated subclasses. Flight muscles of late pupal stage P15, at which time myofibrillogenesis has been completed but the muscle has yet to be used, contain primarily non-phosphorylated variants. A dramatic increase in flightin phosphorylation occurs subsequent to eclosion. As the young adult matures, increasingly phosphorylated variants are generated following a precise ontogenetic progression. Adults 5-6 h old and older contain the entire set of flightin isoelectric variants. All nine phosphovariants remain metabolically active throughout adult life as evidenced by their ability to incorporate radioactive phosphate in older adults. Our results suggest the possibility that all nine phosphorylated variants originate from a single precursor by sequential phosphorylation. Phosphorylation of flightin may thus serve both structural and regulatory functional roles.
果蝇牵张激活飞行肌含有飞行素，这是一种与肌球蛋白丝相互作用的新型肌原纤维蛋白。我们已鉴定出11种飞行素等电变体，可细分为磷酸化和非磷酸化亚类。处于蛹后期P15的飞行肌，此时肌原纤维形成已完成但肌肉尚未使用，主要含有非磷酸化变体。羽化后飞行素磷酸化显著增加。随着年轻成虫成熟，按照精确的个体发育进程产生越来越多的磷酸化变体。5至6小时龄及以上的成虫含有整套飞行素等电变体。所有九种磷酸化变体在成年期始终保持代谢活性，这可通过它们在老龄成虫中掺入放射性磷酸盐的能力得到证明。我们的结果表明，所有九种磷酸化变体可能通过顺序磷酸化源自单一前体。因此，飞行素的磷酸化可能兼具结构和调节功能作用。
