Interaction of ICAM-1 with β2-integrin CD11c/CD18:: Characterization of a peptide ligand that mimics a putative binding site on domain D4 of ICAM-1
Interaction of ICAM-1 with β2-integrin CD11c/CD18:: Characterization of a peptide ligand that mimics a putative binding site on domain D4 of ICAM-1
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DOI：
10.1002/eji.200425914
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发表时间：
2005-12-01
影响因子：
5.4
通讯作者：
Parkos, CA
中科院分区：
文献类型：
--
作者：
Frick, C;Odermatt, A;Parkos, CA
整合素CD 11 c/CD 18在白细胞和细胞基质粘附中起作用，并且在某些造血系统恶性肿瘤中高度表达。为了更好地表征配体结合特性，我们在纯化的CD 11 c/CD 18上淘选随机肽噬菌体展示文库。我们鉴定了表达环状肽C-GRWSGWPADL-C的噬菌体。C-GRWSGWPADL-C噬菌体与表达CD 11 c/CD 18的单核细胞特异性结合，但不与CD 11 c/CD 18阴性淋巴细胞结合，并且与纯化的CD 11 c/CD 18的结合比对照噬菌体高5 × 103倍，而不与CD 11b/CD 18结合。肽序列分析揭示了ICAM-1的结构域D5中的相似序列和结构域D4中的替代性相移基序。表面等离子体共振实验表明ICAM-1和CD 11 c/CD 18直接相互作用。含有ICAM-1胞外区的可溶性融合蛋白可阻断C-GRWSGWPADL-C噬菌体与CD 11 c/CD 18的结合。此外，合成的单体环状肽C-GRWSGWPADL-C特异性结合CD 11 c/CD 18并抑制ICAM-1结合。其相当低的结合亲和力和不能从CD 11 c/CD 18置换五价C-GRWSGWPADL-C噬菌体表明所选肽的多聚体展示对于高亲和力结合是必需的。使用ICAM-1缺失构建体，我们表明结构域D4是与CD 11 c/CD 18相互作用所必需的，这表明C-GRWSGWPADL-C噬菌体通过在结构上模拟ICAM-1的D4上的相互作用位点而特异性结合CD 11 c/CD 18。
The integrin CD11c/CD18 plays a role in leukocyte and cell matrix adhesion and is highly expressed in certain hematopoietic malignancies. To better characterize ligand binding properties, we panned random peptide phage-display libraries over purified CD11c/CD18. We identified a phage expressing the circular peptide C-GRWSGWPADL-C. C-GRWSGWPADL-C phage bound specifically to CD11c/CD18 expressing monocytes but not CD11c/CD18 negative lymphocytes and showed 5x10(3)-fold higher binding to purified CD11c/CD18 than control phage, without binding to CD11b/CD18. Peptide sequence analysis revealed a similar sequence in domain D5 of ICAM-1 and an alternative, phase-shifted motif in domain D4. Surface plasmon resonance experiments demonstrated direct interaction of ICAM-1 and CD11c/CD18. A soluble fusion protein containing the extracellular domain of ICAM-1 abolished C-GRWSGWPADL-C phage binding to CD11c/CD18. Moreover, synthetic monomeric circular peptide C-GRWSGWPADL-C bound specifically to CD11c/CD18 and inhibited ICAM-1 binding. Its rather low binding affinity and inability to displace pentavalent C-GRWSGWPADL-C phage from CD11c/CD18 suggests that a multimeric display of the selected peptide is essential for high affinity binding. Using ICAM-1 deletion constructs, we showed that domain D4 is required for interaction with CD11c/CD18, suggesting that C-GRWSGWPADL-C phage binds specifically to CD11c/CD18 by structurally mimicking the interaction site on D4 of ICAM-1.