Caveolin 3 suppresses phosphorylation-dependent activation of sarcolemmal nNOS.
Caveolin 3 suppresses phosphorylation-dependent activation of sarcolemmal nNOS.
复制标题
Caveolin 3 抑制肌膜 nNOS 的磷酸化依赖性激活。
DOI：
10.1016/j.bbrc.2022.08.066
复制
发表时间：
2022
影响因子：
3.1
通讯作者：
Sunada Y.
中科院分区：
文献类型：
--
作者：
Ohsawa Y;Ohtsubo H;Saito Y;Nishimatsu SI;Hagiwara H;Murakami T;Nishino I;Sunada Y.
小窝蛋白3基因突变导致常染色体显性遗传性肢体带状肌营养不良症(LGMD)1C。在小鼠中，突变型小窝蛋白3的过表达导致小窝蛋白3的丢失，并导致肌纤维萎缩，并伴随着肌膜上神经元型一氧化氮合酶(NNOS)的激活。在这里，我们证明了小窝蛋白3直接与nNOS结合，并在体外抑制其磷酸化依赖的激活，在体外，在靠近还原结构域C末端的烟酰胺腺嘌呤二核苷酸磷酸(NADPH)−黄素腺嘌呤二核苷酸(FAD)模块中的Ser1412。在体外，结构性活性的nNOS促进了成肌细胞的融合，但不能促进肌发生。在小窝蛋白3突变小鼠和LGMD1C患者的肌肉中，nNOS的磷酸化依赖激活。与nNOS突变小鼠交配加剧了小窝蛋白3突变小鼠的肌纤维萎缩。在nNOS突变小鼠中，心脏毒素损伤后再生的肌纤维营养不良，成肌细胞融合减少。给予NO供体增加了小窝蛋白3突变小鼠的肌纤维大小和肌核数量。运动也增加了野生型和小窝蛋白3突变小鼠的肌纤维大小，并伴随着nNOS的磷酸化依赖的激活。这些数据表明，小窝蛋白3抑制依赖于磷酸化的nNOS的激活，从而通过促进成肌细胞融合而导致肌纤维肥大。在小窝蛋白3缺陷的肌肉中，nNOS磷酸化的肥大信号可以起到代偿作用。
Mutations of the caveolin 3 gene cause autosomal dominant limb-girdle muscular dystrophy (LGMD)1C. In mice, overexpression of mutant caveolin 3 leads to loss of caveolin 3 and results in myofiber hypotrophy in association with activation of neuronal nitric oxide synthase (nNOS) at the sarcolemma. Here, we show that caveolin 3 directly bound to nNOS and suppressed its phosphorylation-dependent activation at a specific residue, Ser1412 in the nicotinamide adenine dinucleotide phosphate (NADPH)−flavin adenine dinucleotide (FAD) module near the C-terminus of the reduction domain,in vitro. Constitutively active nNOS enhanced myoblast fusion, but not myogenesis,in vitro. Phosphorylation-dependent activation of nNOS occurred in muscles from caveolin 3-mutant mice and LGMD1C patients. Mating with nNOS-mutant mice exacerbated myofiber hypotrophy in the caveolin 3-mutant mice. In nNOS-mutant mice, regenerating myofibers after cardiotoxin injury became hypotrophic with reduced myoblast fusion. Administration of NO donor increased myofiber size and the number of myonuclei in the caveolin 3-mutant mice. Exercise also increased myofiber size accompanied by phosphorylation-dependent activation of nNOS in wild-type and caveolin 3-mutant mice. These data indicate that caveolin 3 inhibits phosphorylation-dependent activation of nNOS, which leads to myofiber hypertrophy via enhancing myoblast fusion. Hypertrophic signaling by nNOS phosphorylation could act in a compensatory manner in caveolin 3-deficient muscles.