Skeletal muscle calcineurin: influence of phenotype adaptation and atrophy.
Skeletal muscle calcineurin: influence of phenotype adaptation and atrophy.
复制标题
DOI：
10.1152/ajpregu.2001.280.4.r1256
复制
发表时间：
2001-04
期刊：
影响因子：
--
通讯作者：
E. Spangenburg;J. Williams;R. Roy;R. Talmadge
中科院分区：
文献类型：
--
作者：
E. Spangenburg;J. Williams;R. Roy;R. Talmadge
钙调磷酸酶（CaN）被认为是一种信号分子，可以将生理刺激（如收缩活动）转化为启动慢纤维表型基因表达和肌肉生长的分子信号。为了确定肌肉表型和萎缩对肌肉中CaN水平的影响，通过肌球蛋白重链(MHC)-异构体比例评估不同表型大鼠肌肉中可溶性CaN水平，采用Western blotting测定。与比目鱼肌（主要是I型MHC）或股中间肌（VI，包含所有4种成年MHC亚型）相比，以快速（IIx和IIb） MHC亚型为主的足底肌的CaN水平明显更高。完全脊髓横断（ST）后3个月，尽管快速MHC亚型显著增加，但VI肌肉中的CaN水平显著降低。令人惊讶的是，在ST和对照大鼠中，VI中的CaN水平与肌肉质量高度相关，而与MHC异构体比例无关。这些数据表明，骨骼肌中的CaN水平与肌肉质量高度相关，ST后与表型的正常关系消失。
Calcineurin (CaN) has been implicated as a signaling molecule that can transduce physiological stimuli (e.g., contractile activity) into molecular signals that initiate slow-fiber phenotypic gene expression and muscle growth. To determine the influence of muscle phenotype and atrophy on CaN levels in muscle, the levels of soluble CaN in rat muscles of varying phenotype, as assessed by myosin heavy chain (MHC)-isoform proportions, were determined by Western blotting. CaN levels were significantly greater in the plantaris muscle containing predominantly fast (IIx and IIb) MHC isoforms, compared with the soleus (predominantly type I MHC) or vastus intermedius (VI, contains all 4 adult MHC isoforms). Three months after a complete spinal cord transection (ST), the CaN levels in the VI muscle were significantly reduced, despite a significant increase in fast MHC isoforms. Surprisingly, the levels of CaN in the VI were highly correlated with muscle mass but not MHC isoform proportions in ST and control rats. These data demonstrate that CaN levels in skeletal muscle are highly correlated to muscle mass and that the normal relationship with phenotype is lost after ST.