ap Gwynn I, Kemp R B, Jones B M
Cell Tissue Res. 1976 Aug 26;171(3):351-8. doi: 10.1007/BF00224659.
125I-labelled sheep anti-rabbit gamma-globulin antibodies were used to locate rabbit antibodies to smooth- and striated-muscle actomyosins at the surface of trypsin-dissociated embryonic chick cells. Statistical analysis of electron microscope autoradiographs revealed that the plasma membrane of these cells was significantly labelled with both antibodies. Further tests revealed that there were a significantly greater number of antigenic sites present on the cell surface for the gizzard smooth-muscle antibodies than for those against pectoralis straited-muscle actomyosin. It was further shown that both the rate and extent of binding of the 125I-labelled smooth-muscle actomyosin antibodies to the cells were greater than for anti-straited-muscle gamma-globulins. Binding of the former was reduced to a level similar to that of 125I-NIS conjugate by preincubation of the gamma-globulins with smooth-muscle heavy meromyosin, while a simiar reduction was observed when anti-pectoralis actomyosin was treated with actin. It was concluded that actin- and myosin-like proteins must now be considered as integral components of the plasma membrane.
用125I标记的羊抗兔γ球蛋白抗体来定位胰蛋白酶解离的鸡胚细胞表面针对平滑肌和横纹肌肌动球蛋白的兔抗体。对电子显微镜放射自显影片的统计分析显示，这些细胞的质膜被两种抗体显著标记。进一步测试表明，砂囊平滑肌抗体在细胞表面的抗原位点数量明显多于针对胸肌横纹肌肌动球蛋白的抗体。进一步表明，125I标记的平滑肌肌动球蛋白抗体与细胞结合的速率和程度都高于抗横纹肌γ球蛋白。通过将γ球蛋白与平滑肌重酶解肌球蛋白预孵育，前者的结合降低到与125I-NIS缀合物相似的水平，而当用肌动蛋白处理抗胸肌肌动球蛋白时也观察到类似的降低。得出的结论是，肌动蛋白样和肌球蛋白样蛋白现在必须被视为质膜的组成成分。
