Haugen P K, McCarthy J B, Skubitz A P, Furcht L T, Letourneau P C
Department of Cell Biology, University of Minnesota, Minneapolis 55455.
J Cell Biol. 1990 Dec;111(6 Pt 1):2733-45. doi: 10.1083/jcb.111.6.2733.
Cellular interactions with fibronectin-treated substrata have a complex molecular basis involving multiple domains. A carboxy-terminal cell and heparin binding region of fibronectin (FN) is particularly interesting because it is a strong promoter of neurite outgrowth (Rogers, S.L., J.B. McCarthy, S.L. Palm, L.T. Furcht, and P.C. Letourneau, 1985. J. Neurosci. 5:369-378) and cell attachment (McCarthy, J.B., S.T. Hagen, and L.T. Furcht. 1986. J. Cell Biol. 102:179-188). To further understand the molecular mechanisms of neuronal interactions with this region of FN, we screened two peptides from the 33-kD heparin binding fragment of the FN A chain, FN-C/H II (KNNQKSEPLIGRKKT) and CS1 (Humphries, M.J., A. Komoriya, S.K. Akiyama, K. Olden, and K.M. Yamada. 1987. J. Biol. Chem. 262:6886-6892), for their ability to promote B104 neuroblastoma cell-substratum adhesion and neurite outgrowth. Both FN-C/H II and CS1 promoted B104 cell attachment in a concentration-dependent and saturable manner, with attachment to FN-C/H II exceeding attachment to CS1. In solution, both exogenous FN-C/H II or CS1 partially inhibited cell adhesion to the 33-kD fragment. Similar results were obtained with anti-FN-C/H II antibodies. In contrast, soluble GRGDSP did not affect B104 cell adhesion to FN-C/H II. These results indicate that both FN-C/H II and CS1 represent distinct, RGD-independent, cell adhesion-promoting sites active within the 33-kD fragment, and further define FN-C/H II as a novel neural recognition sequence in FN. B104 adhesion to FN-C/H II and CS1 differs in sensitivity to heparin, yet each peptide inhibited adhesion to the other peptide, suggesting cell adhesion is somehow related at the cellular level. Within the A chain 33-kD fragment, FN-C/H II and CS1 are contiguous, and might represent components of a larger domain with greater neurite-promoting activity since only the 33-kD fragment, and neither individual peptide, was effective at promoting B104 neurite outgrowth. These data further support the hypothesis that cell responses to FN are mediated by multiple sites involving both heparin-sensitive and -insensitive mechanisms.
细胞与纤连蛋白处理的基质之间的相互作用具有复杂的分子基础，涉及多个结构域。纤连蛋白（FN）的羧基末端细胞和肝素结合区域特别有趣，因为它是神经突生长（罗杰斯，S.L.，J.B.麦卡锡，S.L.帕尔姆，L.T.弗奇特，和P.C.勒图尔诺，1985年。《神经科学杂志》5:369 - 378）和细胞附着（麦卡锡，J.B.，S.T.哈根，和L.T.弗奇特。1986年。《细胞生物学杂志》102:179 - 188）的强促进剂。为了进一步了解神经元与FN这一区域相互作用的分子机制，我们从FN A链的33-kD肝素结合片段中筛选了两种肽，FN-C/H II（KNNQKSEPLIGRKKT）和CS1（汉弗莱斯，M.J.，A.小森弥，S.K.秋山，K.奥尔登，和K.M.山田。1987年。《生物化学杂志》262:6886 - 6892），以研究它们促进B104神经母细胞瘤细胞与基质黏附及神经突生长的能力。FN-C/H II和CS1都以浓度依赖和饱和的方式促进B104细胞附着，且与FN-C/H II的附着超过与CS1的附着。在溶液中，外源性FN-C/H II或CS1都部分抑制细胞与33-kD片段的黏附。抗FN-C/H II抗体也得到了类似结果。相比之下，可溶性GRGDSP不影响B104细胞与FN-C/H II的黏附。这些结果表明，FN-C/H II和CS1都代表33-kD片段内不同的、不依赖RGD的、促进细胞黏附的活性位点，并进一步将FN-C/H II定义为FN中的一个新的神经识别序列。B104对FN-C/H II和CS1的黏附对肝素的敏感性不同，但每种肽都抑制对另一种肽的黏附，这表明细胞黏附在细胞水平上以某种方式相关。在A链33-kD片段内，FN-C/H II和CS1是相邻的，可能代表一个具有更强神经突促进活性的更大结构域的组成部分，因为只有33-kD片段，而不是单个肽，能有效促进B104神经突生长。这些数据进一步支持了这样的假设，即细胞对FN的反应是由涉及肝素敏感和不敏感机制的多个位点介导的。
