Cell type-specific differences in glycosaminoglycans modulate the biological activity of a heparin-binding peptide (RKRLQVQLSIRT) from the G domain of the laminin α1 chain
Cell type-specific differences in glycosaminoglycans modulate the biological activity of a heparin-binding peptide (RKRLQVQLSIRT) from the G domain of the laminin α1 chain
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DOI：
10.1074/jbc.m100774200
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发表时间：
2001-06-22
影响因子：
4.8
通讯作者：
Kleinman, HK
中科院分区：
文献类型：
--
作者：
Hoffman, MP;Engbring, JA;Kleinman, HK
AG 73（RKRLQVQLSIRT）是一种来自层粘连蛋白α 1链G结构域的肽，对不同的细胞类型具有不同的生物学活性。人唾液腺细胞上多配体蛋白聚糖-1的硫酸乙酰肝素侧链先前被鉴定为AG 73的细胞表面配体。我们使用来自其他层粘连蛋白Cu链（A2 G73-A5 G73）的同源肽来确定AG 73序列的生物活性是否是保守的。人唾液腺细胞和小鼠黑色素瘤细胞系（B16 F10）都结合的肽，但细胞附着抑制糖胺聚糖，改性肝素，和大小肝素片段在细胞类型特异性的方式。在其他试验中，AG 73，而不是同源肽，抑制唾液腺的分支形态发生和基质胶上的B16 F10网络形成。我们使用具有氨基酸取代和截短的肽鉴定了对AG 73生物活性至关重要的残基。与抑制基质胶上B16 F10网络形成所需的残基（N-末端XxRLQVQLSIRT）相比，更少的残基是抑制分支形态发生（XKXLXVXXXIRT）的关键。此外，表面等离子体共振分析鉴定了序列的C-末端IRT对于肝素结合是重要的。基于结构的序列比对预测AG 73在P-折叠中具有G结构域表面上的N-末端K（Lys（2））和C-末端R（Arg（10））。总之，我们已经确定，细胞表面糖胺聚糖的差异和细胞识别的AG 73中氨基酸的差异调节肽的生物活性，并提供了一种机制来解释其细胞特异性活性。
AG73 (RKRLQVQLSIRT), a peptide from the G domain of the laminin alpha1 chain, has diverse biological activities with different cell types, The heparan sulfate side chains of syndecan-1 on human salivary gland cells were previously identified as the cell surface ligand for AG73. We used homologous peptides from the other laminin cu-chains (A2G73-A5G73) to determine whether the bioactivity of the AG73 sequence is conserved. Human salivary gland cells and a mouse melanoma cell line (B16F10) both bind to the peptides, but cell attachment was inhibited by glycosaminoglycans, modified heparin, and sized heparin fragments in a cell type-specific manner. In other assays, AG73, but not the homologous peptides, inhibited branching morphogenesis of salivary glands and B16F10 network formation on Matrigel. We identified residues critical for AG73 bioactivity using peptides with amino acid substitutions and truncations. Fewer residues were critical for inhibiting branching morphogenesis (XKXLXVXXXIRT) than those required to inhibit B16F10 network formation on Matrigel (N-terminal XxRLQVQLSIRT). In addition, surface plasmon resonance analysis identified the C-terminal IRT of the sequence to be important for heparin binding. Structure based sequence alignment predicts AG73 in a P-sheet with the N-terminaI K (Lys(2)) and the C-terminal R (Arg(10)) on the surface of the G domain. In conclusion, we have determined that differences in cell surface glycosaminoglycans and differences in the amino acids in AG73 recognized by cells modulate the biological activity of the peptide and provide a mechanism to explain its cell-specific activities.