STRUCTURE-FUNCTION ANALYSIS OF HEPATOCYTE GROWTH-FACTOR - IDENTIFICATION OF VARIANTS THAT LACK MITOGENIC ACTIVITY YET RETAIN HIGH-AFFINITY RECEPTOR-BINDING
STRUCTURE-FUNCTION ANALYSIS OF HEPATOCYTE GROWTH-FACTOR - IDENTIFICATION OF VARIANTS THAT LACK MITOGENIC ACTIVITY YET RETAIN HIGH-AFFINITY RECEPTOR-BINDING
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DOI：
10.1002/j.1460-2075.1992.tb05315.x
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发表时间：
1992-07-01
期刊：
影响因子：
11.4
通讯作者：
GODOWSKI, PJ
中科院分区：
文献类型：
--
作者：
LOKKER, NA;MARK, MR;GODOWSKI, PJ
肝细胞生长因子 (HGF) 是肝实质、上皮细胞和内皮细胞的有效有丝分裂原。在结构上，它与含三环的丝氨酸蛋白酶相似，尽管它不具有蛋白水解活性。通过 HGF 取代和缺失变体的功能分析进行了人 HGF 的结构-活性关系研究。 HGF 变体的分析是通过确定它们在原代培养物中诱导肝细胞 DNA 合成以及与野生型 HGF 竞争结合可溶形式的 HGF 受体的能力来完成的。进行了三组变体：（i）切割位点处的取代，（ii）蛋白酶样结构域内的取代和（iii）β链和/或三环结构域的删除。我们的结果表明：（i）单链HGF是一种类似酶原的促分裂原，因为生物活性需要裂解成双链形式，然而，单链形式的HGF仍然保留了大量的受体结合能力； (ii) 蛋白酶样结构域中的某些突变导致完全有丝分裂活性缺陷的变体，但表现出与野生型 HGF 相似的明显受体结合亲和力（K(d) 约为 50-70 pM）； (iii)与野生型HGF相比，含有成熟HGF N端272个残基的变体仅显示K(d)增加4倍，表明主要受体结合决定簇位于该序列内。
Hepatocyte growth factor (HGF) is a potent mitogen for parenchymal liver, epithelial and endothelial cells. Structurally, it has similarities to kringle-containing serine proteases, although it does not possess proteolytic activity. A structure-activity relationship study of human HGF was performed by functional analysis of HGF substitution and deletion variants. Analysis of HGF variants was accomplished by defining their ability to induce DNA synthesis on hepatocytes in primary culture and to compete with wild-type HGF for binding to a soluble form of the HGF receptor. Three groups of variants were made: (i) substitutions at the cleavage site, (ii) substitutions within the protease-like domain and (iii) deletions of the beta-chain and/or kringle domains. Our results show that: (i) single-chain HGF is a zymogen-like promitogen in that cleavage into a two-chain form is required for biological activity, however, the single chain form of HGF still retains substantial receptor binding capacity; (ii) certain mutations in the protease-like domain result in variants that are completely defective for mitogenic activity, yet exhibit apparent receptor binding affinities similar to wild-type HGF (K(d) approximately 50-70 pM); and (iii) a variant containing the N-terminal 272 residues of mature HGF showed only a 4-fold increase in K(d) when compared with wild-type HGF indicating that a primary receptor binding determinant is located within this sequence.