Insights into the structure/function of hepatocyte growth factor/scatter factor from studies with individual domains
Insights into the structure/function of hepatocyte growth factor/scatter factor from studies with individual domains
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DOI：
10.1016/j.jmb.2006.12.061
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发表时间：
2007-03-23
影响因子：
5.6
通讯作者：
Gherardi, E.
中科院分区：
文献类型：
--
作者：
Holmes, O.;Pillozzi, S.;Gherardi, E.
肝细胞生长因子/分散因子(HGF/SF)是由原癌基因c-Met编码的受体酪氨酸激酶的配体，是一种结构上与酶原纤溶酶原相关的多结构域蛋白，在发育、组织再生和癌症中发挥重要作用。(1)我们在酵母或哺乳动物细胞中分别表达了HGF/SF的N-末端(N)结构域、四个Kringle结构域(K1~K4)和丝氨酸蛋白酶同源结构域(SP)，并研究了它们与Met受体以及硫酸乙酰肝素和硫酸皮肤素共受体结合的能力。(Ii)在靶细胞中激活Met，(Iii)将它们的结合位点映射到Met的β-螺旋桨结构域上。N、K1和SP结构域与蛋氨酸直接结合，具有相似的亲和力(K-d=2.4、3.3和1.4muM)。相同的结构域也与亲和力递减的肝素结合(N>；K1>；>；SP)，但仅与N结构域结合的硫酸皮肤素结合。三个Kringle结构域(K1、K2和K4)在靶细胞上显示激动性活性。相反，N和SP结构域虽然能够与Met结合，但没有或几乎没有活性。进一步的交联实验表明，N结构域和Kringles 1-2都与Metβ-推进器的β-链部分(氨基酸残基308-514)结合。总之，HGF/SF的K1、K2和K4结构域足以激活Met，而N和SP结构域则不足以激活Met，尽管后者为全长HGF/SF的受体激活提供了额外的结合位点。这些结果为HGF/SF的结构和功能提供了新的见解，并为设计N和K1结构域作为受体拮抗剂用于癌症治疗奠定了基础。(C)2007爱思唯尔有限公司。保留所有权利。
Hepatocyte growth factor/scatter factor (HGF/SF), the ligand for the receptor tyrosine kinase encoded by the c-Met proto-oncogene, is a multidomain protein structurally related to the pro-enzyme plasminogen and with major roles in development, tissue regeneration and cancer.(1) We have expressed the N-terminal (N) domain, the four kringle domains (K1 to K4) and the serine proteinase homology domain (SP) of HGF/SF individually in yeast or mammalian cells and studied their ability to: (i) bind the Met receptor as well as heparan sulphate and dermatan sulphate co-receptors, (ii) activate Met in target cells and, (iii) map their binding sites onto the beta-propeller domain of Met. The N, K1 and SP domains bound Met directly with comparable affinities (K-d = 2.4, 3.3 and 1.4 mu M). The same domains also bound heparin with decreasing affinities (N > K1 >> SP) but only the N domain bound dermatan sulphate. Three kringle domains (K1, K2 and K4) displayed agonistic activity on target cells. In contrast, the N and SP domains, although capable of Met binding, displayed no or little activity. Further, cross-linking experiments demonstrated that both the N domain and kringles 1-2 bind the beta-chain moiety (amino acid residues 308-514) of the Met beta-propeller. In summary, the K1, K2 and K4 domains of HGF/SF are sufficient for Met activation, whereas the N and SP domains are not, although the latter domains contribute additional binding sites necessary for receptor activation by full length HGF/SF. The results provide new insights into the structure/ function of HGF/SF and a basis for engineering the N and K1 domains as receptor antagonists for cancer therapy. (c) 2007 Elsevier Ltd. All rights reserved.