Inoue Masahiko, Wakayama Yoshihiro, Jimi Takahiro, Shibuya Seiji, Hara Hajime, Unaki Akihiko, Kenmochi Kiyokazu
Department of Neurology, Showa University Fujigaoka Hospital, Aoba-ku, Yokohama, Japan.
Nagoya J Med Sci. 2008 Aug;70(3-4):117-26.
Syntrophins are the cytoplasmic peripheral proteins of dystrophin glycoprotein complex, of which five (alpha l, beta 1, beta 2, gamma 1 and gamma 2) isoforms have been identified so far. Respective syntrophin isoforms are encoded by different genes but have similar domain structures. At the sarcolemma of skeletal muscle, the most abundant alpha l-syntrophin was shown to interact at its PDZ domain with many membrane proteins. Among them, the AQP4 interaction with alpha 1-syntrophin PDZ domain was demonstrated by a Tg mouse study, prompting us to investigate the interaction between mouse alpha l-syntrophin (BC018546: nt.267-492, PDZ domain) pEXP-AD502 as prey vector and mouse AQP4 (NM009700: nt.805-969) pDBLeu as bait vector by the yeast two-hybrid assay, resulting in a negative study. We further studied the binding partner of another sarcolemma located beta 1-syntrophin, and performed a yeast two-hybrid experiment. With human beta 1-syntrophin as bait and human skeletal muscle cDNA library as prey, we obtained one positive clone which turned out to be alpha-dystrobrevin. Although the interaction of human beta 1-syntrophin with alpha-dystrobrevin has already been shown by immunoprecipitation assay, we have here confirmed this interaction by a yeast two-hybrid experiment.
肌养蛋白是肌营养不良蛋白糖蛋白复合体的胞质外周蛋白，目前已鉴定出五种（α1、β1、β2、γ1和γ2）亚型。各自的肌养蛋白亚型由不同基因编码，但具有相似的结构域结构。在骨骼肌的肌膜上，最丰富的α1-肌养蛋白在其PDZ结构域与许多膜蛋白相互作用。其中，通过转基因小鼠研究证实了水通道蛋白4（AQP4）与α1-肌养蛋白PDZ结构域的相互作用，这促使我们通过酵母双杂交实验研究小鼠α1-肌养蛋白（BC018546：核苷酸267 - 492，PDZ结构域）pEXP-AD502作为猎物载体与小鼠AQP4（NM0（此处疑似有误，推测应为NM009700）：核苷酸805 - 969）pDBLeu作为诱饵载体之间的相互作用，结果为阴性研究。我们进一步研究了另一种位于肌膜的β1-肌养蛋白的结合伴侣，并进行了酵母双杂交实验。以人β1-肌养蛋白作为诱饵，人骨骼肌cDNA文库作为猎物，我们获得了一个阳性克隆，结果证明是α-肌营养不良蛋白短链。尽管人β1-肌养蛋白与α-肌营养不良蛋白短链的相互作用已通过免疫沉淀实验得到证实，但我们在此通过酵母双杂交实验再次证实了这种相互作用。
