Woods A, Longley R L, Tumova S, Couchman J R
Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama, 35294-0019, USA.
Arch Biochem Biophys. 2000 Feb 1;374(1):66-72. doi: 10.1006/abbi.1999.1607.
Cell adhesion to extracellular matrix involves signaling mechanisms which control attachment, spreading and the formation of focal adhesions and stress fibers. Fibronectin can provide sufficient signals for all three processes, even when protein synthesis is prevented by cycloheximide. Primary fibroblasts attach and spread following integrin ligation, but do not form focal adhesions unless treated with a heparin-binding fragment of fibronectin (HepII), a peptide from this domain, or phorbol esters to activate protein kinase C. Syndecan-4 heparan sulfate proteoglycan is a transmembrane component present together with integrins in focal adhesions. Syndecan-4 binds and activates protein kinase Calpha, whose activity is needed for focal adhesion formation. We now report that the glycosaminoglycan chains of syndecan-4 bind recombinant HepII and it is incorporated into forming focal adhesions.
细胞与细胞外基质的黏附涉及控制附着、铺展以及黏着斑和应力纤维形成的信号传导机制。纤连蛋白能够为这三个过程提供充足的信号，即便蛋白质合成被放线菌酮抑制时也是如此。原代成纤维细胞在整合素连接后会附着并铺展，但除非用纤连蛋白的肝素结合片段（HepII）、该结构域的一种肽或佛波酯处理以激活蛋白激酶C，否则不会形成黏着斑。Syndecan-4硫酸乙酰肝素蛋白聚糖是一种跨膜成分，与整合素一起存在于黏着斑中。Syndecan-4结合并激活蛋白激酶Cα，其活性是形成黏着斑所必需的。我们现在报告，Syndecan-4的糖胺聚糖链结合重组HepII，并被整合到正在形成的黏着斑中。
