Volk T, Fessler L I, Fessler J H
Molecular Biology Institute, University of California, Los Angeles 90024-1606.
Cell. 1990 Nov 2;63(3):525-36. doi: 10.1016/0092-8674(90)90449-o.
We propose that integrins help to coordinate the differentiation of the internal, sarcomeric cytoarchitecture of a muscle fiber with its immediate environment and are essential for correct integration of muscle cells into tissue. We found that integrin alpha PS2 beta PS accumulated at contact regions of Drosophila embryo cells cultured in D-22 medium on Drosophila laminin. Myotubes formed, but subsequent addition of serum or fibronectin was needed for sarcomere formation: integrin and actin became concentrated at Z-bands; myosin and actin occurred between the Z-bands. This change failed to occur in the multinucleate myotubes derived from integrin beta PS null myospheroid mutants. In normal embryos/early larvae, integrin was located at Z-bands and at muscle insertions. Myogenesis and Z-bands were defective in myospheroid embryos. Attachment, spreading, and growth of myoblasts and neurons on the laminin substrate utilized different binding proteins and were independent of integrin.
我们提出，整合素有助于协调肌纤维内部肌节细胞结构与其紧邻环境之间的分化，并且对于肌肉细胞正确整合到组织中至关重要。我们发现，整合素αPS2βPS在果蝇层粘连蛋白上于D-22培养基中培养的果蝇胚胎细胞的接触区域积累。肌管形成了，但肌节形成需要随后添加血清或纤连蛋白：整合素和肌动蛋白在Z带处浓缩；肌球蛋白和肌动蛋白出现在Z带之间。这种变化在源自整合素βPS缺失的肌球样突变体的多核肌管中未发生。在正常胚胎/早期幼虫中，整合素位于Z带和肌肉附着处。肌球样胚胎中的肌生成和Z带存在缺陷。成肌细胞和神经元在层粘连蛋白底物上的附着、铺展和生长利用了不同的结合蛋白，且与整合素无关。
