Bähler M, Wallimann T, Eppenberger H M
J Muscle Res Cell Motil. 1985 Dec;6(6):783-800. doi: 10.1007/BF00712242.
A-segments, native thick filaments, frayed filaments, bare zone assemblages, as well as completely disassembled and reassembled thick filaments from chicken pectoralis major were investigated for the presence of M-band proteins by the colloidal gold labelling technique. Specific polyclonal antibodies against the three M-band proteins identified to date, MM-creatine kinase, M-protein (165 kDa) and a 185 kDa protein myomesin, were prepared. Incubation with anti-M-protein and anti-myomesin antibodies resulted in heavy labelling of all thick filament types mentioned above, with the exception of the completely disassembled and reassembled thick filaments. In that case no labelling was detected with either antibody. In contrast, MM-creatine kinase which is an integral component of the intact M-band structure was detectable on isolated native thick filaments with lower frequency and to a variable extent. Also, bare zone assemblages were only rarely labelled by anti-MM-creatine kinase antibodies. This study shows that the 'cuff-like' additional material which had previously been observed in the middle of the bare zone of isolated thick filaments represent remnants of all three M-band proteins, whereas the extra material in intact bare zone assemblages mainly consists of myomesin and M-protein, but not of MM-creatine kinase. Myomesin and M-line protein may be important for the assembly and structural maintenance of thick filaments as well as for anchoring of additional M-band proteins, e.g. MM-creatine kinase which is bound less tightly to thick filaments and, in accordance with earlier results, seems to represent within the M-band some of the prominent bridge-forming structures.
运用胶体金标记技术，对鸡胸大肌中的A段、天然粗肌丝、磨损的肌丝、裸区组合，以及完全拆解并重新组装的粗肌丝进行研究，以检测M带蛋白的存在情况。制备了针对迄今已鉴定出的三种M带蛋白的特异性多克隆抗体，分别是MM-肌酸激酶、M蛋白（165 kDa）和185 kDa的肌间蛋白。用抗M蛋白和抗肌间蛋白抗体孵育后，上述所有类型的粗肌丝均出现大量标记，但完全拆解并重新组装的粗肌丝除外，在这种情况下，两种抗体均未检测到标记。相比之下，作为完整M带结构不可或缺组成部分的MM-肌酸激酶，在分离出的天然粗肌丝上以较低频率且在不同程度上可检测到。此外，裸区组合仅偶尔被抗MM-肌酸激酶抗体标记。这项研究表明，先前在分离出的粗肌丝裸区中部观察到的“袖口状”额外物质代表了所有三种M带蛋白的残余物，而完整裸区组合中的额外物质主要由肌间蛋白和M蛋白组成，而非MM-肌酸激酶。肌间蛋白和M线蛋白可能对粗肌丝的组装和结构维持以及额外M带蛋白的锚定很重要，例如MM-肌酸激酶与粗肌丝的结合较松散，根据早期结果，它似乎在M带中代表一些突出的桥形成结构。
