CELL-TYPE-SPECIFIC ADHESIVE INTERACTIONS OF SKELETAL MYOBLASTS WITH THROMBOSPONDIN-1
CELL-TYPE-SPECIFIC ADHESIVE INTERACTIONS OF SKELETAL MYOBLASTS WITH THROMBOSPONDIN-1
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DOI：
10.1091/mbc.5.4.423
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发表时间：
1994-04-01
影响因子：
3.3
通讯作者：
LAWLER, J
中科院分区：
文献类型：
--
作者：
ADAMS, JC;LAWLER, J
血小板反应蛋白-1（TSP-1）是一种细胞外基质糖蛋白，可能在骨骼肌的形态发生和修复中发挥重要作用。为了开始探索血小板反应蛋白-1在该组织中的作用，我们研究了三种啮齿动物骨骼肌细胞系C2 C12、G8和H9 c2与血小板TSP-1的相互作用。细胞分泌血小板反应蛋白并将其以不同于纤连蛋白的分布掺入细胞层中。成肌细胞附着并在纤连蛋白或血小板反应蛋白包被的基质上扩散，具有相似的时间和浓度依赖性。而纤维连接蛋白上的细胞粘附组织肌动蛋白应力纤维，TSP-1上的细胞粘附显示突出的膜皱褶和lampellet，含有放射状肌动蛋白微刺。与血小板反应蛋白-1或140-kDa胰蛋白酶片段的连接是通过与1型重复序列和羧基末端球状结构域的相互作用介导的。肝素、GRGDSP肽或VTCG肽不抑制附着，但硫酸软骨素A抑制附着。PI或α V亚组的整合素似乎不参与成肌细胞与TSP-1的附着;相反，该过程部分取决于细胞表面硫酸软骨素蛋白聚糖。而中央70 kDa的胰凝乳蛋白酶片段的TSP-1不支持成肌细胞附着，TSP-1的羧基末端结构域作为融合蛋白在细菌表达载体，pGEX，支持成肌细胞附着到30%的完整的TSP-1的水平。血小板反应蛋白-4（TSP-4）也存在于骨骼肌中，含有TSP-4的羧基末端结构域的融合蛋白也支持成肌细胞粘附，尽管这种蛋白在摩尔基础上的活性低于TSP-1融合蛋白。因此，TSP-1的羧基末端结构域似乎含有成肌细胞的主要附着位点，并且这种活性存在于血小板反应蛋白家族的第二个成员中。
Thrombospondin-1 (TSP-1) is an extracellular matrix glycoprotein that may play important roles in the morphogenesis and repair of skeletal muscle. To begin to explore the role of thrombospondin-1 in this tissue, we have examined the interactions of three rodent skeletal muscle cell lines, C2C12, G8, and H9c2, with platelet TSP-1. The cells secrete thrombospondin and incorporate it into the cell layer in a distribution distinct from that of fibronectin. Myoblasts attach and spread on fibronectin- or thrombospondin-coated substrates with similar time and concentration dependencies. Whereas cells adherent on fibronectin organize actin stress fibers, cells adherent on TSP-1 display prominent membrane ruffles and lamellae that contain radial actin microspikes. Attachment to thrombospondin-1 or the 140-kDa tryptic fragment is mediated by interactions with the type 1 repeats and the carboxyterminal globular domain. Attachment is not inhibited by heparin, GRGDSP peptide, or VTCG peptide but is inhibited by chondroitin sulphate A. Integrins of the pi or alpha v subgroups do not appear to be involved in myoblast attachment to TSP-1; instead, this process depends in part on cell surface chondroitin sulphate proteoglycans. Whereas the central 70-kDa chymotryptic fragment of TSP-1 does not support myoblast attachment, the carboxy-terminal domain of TSP-1 expressed as a fusion protein in the bacterial expression vector, pGEX, supported myoblast attachment to 30% the level of intact TSP-1. Thrombospondin-4 (TSP-4) is also present in skeletal muscle and a fusion protein containing the carboxy-terminal domain of TSP-4 also supported myoblast adhesion, although this protein was less active on a molar basis than the TSP-1 fusion protein. Thus, the carboxyterminal domain of TSP-1 appears to contain a primary attachment site for myoblasts, and this activity is present in a second member of the thrombospondin family.