隔离和表征kininogen-binding蛋白质p33的内皮细胞。身份gC1q受体。
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柯尔尼Herwald H, Dedio J R,厕所,muller - esterl W
隔离和表征kininogen-binding蛋白质p33的内皮细胞。身份gC1q受体。
生物化学杂志。1996年5月31日;271 (22):13040 - 7。
- PubMed ID
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8662673 (在PubMed]
- 文摘
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激肽原的前体蛋白作用于血管的细胞分裂素,结合具体来说,可逆,饱和血小板,中性白细胞和内皮细胞。两个域激肽原暴露的主要细胞结合位点:共享域D3 H - L-kininogen和域D5H H-kininogen只存在。之前我们已经绘制了激肽原细胞结合位点27残留D3 (“LDC27”)和20残留D5H(分别为“HKH20”“(Herwald H。哈桑,a . a K。Godovac-Zimmermann, J。Schmaier, a . H。muller - esterl, w(1995)生物。化学。270年,14634 - 14642;哈桑,a . a K。电影,d . B。Herwald, H。Schmaier, a . H。muller - esterl, w(1995)生物。270年化学,19256 - 19261)。 The corresponding kininogen acceptor site(s) exposed by the cell surfaces are still poorly defined. Using a non-ionic detergent, Nonidet P-40, we have been able to solubilize kininogen binding sites from an endothelial cell line, EA.hy926, in their functionally active form. Affinity chromatography of the solubilized kininogen binding sites on HKH20, a synthetic peptide representing the D5H cell binding site, allowed us to isolate a 33-kDa protein ("p33") that binds specifically and reversibly to H-kininogen with a KD (apparent dissociation constant) of 9 +/- 2 nM. Preparative SDS electrophoresis followed by NH2-terminal amino acid sequence analysis identified the kininogen-binding protein p33 as the gC1q receptor ("gC1qR"), an extrinsic membrane protein that interacts with the globular domains of the complement component C1q. The purified p33 binds C1q with moderate affinity, KD = 240 +/- 10 nM. Recombinant expression of the corresponding cDNA in Escherichia coli demonstrated that p33 binds H-kininogen, but not L-kininogen. Peptide HKH20 but not peptide LDC27 inhibited binding of H-kininogen to the recombinant p33 in a concentration-dependent manner, indicating that H-kininogen binds to p33 via domain D5H. Recombinant p33 efficiently inhibited the binding of H-kininogen to EA.hy926 cells. Factor XII, but not prekallikrein, competed with H-kininogen binding to p33. These findings suggest that an endothelial binding protein mediates the assembly of critical components of the kinin-generating pathway on the surface of endothelial cells, thereby linking the early events of kinin formation and complement activation.