PLEIOTROPIC EFFECTS OF ANTITHROMBIN STRAND 1C SUBSTITUTION MUTATIONS
PLEIOTROPIC EFFECTS OF ANTITHROMBIN STRAND 1C SUBSTITUTION MUTATIONS
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DOI：
10.1172/jci116133
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发表时间：
1992-12-01
影响因子：
15.9
通讯作者：
THEIN, SL
中科院分区：
文献类型：
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作者：
LANE, DA;OLDS, RJ;THEIN, SL
在抗凝血酶链1C和通向4B链的多肽(F402S、F402C、F402L、A404T、N405K和P407T)的4个不同氨基酸残基上发现了6种不同的替代突变，并与7个受静脉血栓栓塞病影响的独立家系(Rosny、Torino、Maison-Laffitte、Paris 3、La Rochelle、布达佩斯5和奥斯陆)的功能性抗凝血酶缺乏症有关。在所有7个家系中，通过交叉免疫电泳法检测到具有肝素结合异常的各种抗凝血酶，其中6个家系的血浆抗凝血酶抗原浓度降低。经肝素-琼脂糖层析和免疫亲和层析纯化的两个变异型抗凝血酶Rosny和Torino，在体外显著降低了肝素辅因子和递增抑制物的活性。这些突变体与凝血酶的缺陷相互作用可能是由于s1C接近反应部位所致，而循环水平的降低可能与s1C接近高度保守的内部β链有关，这些链含有可能影响丝氨酸周转和细胞内降解的元件。相反，s1C在空间上远离形成抗凝血酶的肝素结合部位的带正电的表面；因此，s1C突变体的肝素结合性质的改变可能反映了反应部位和分子肝素结合区之间的构象连接。这项工作证明了链1C及其邻近的点突变对这种丝氨酸具有多重或多效性的影响，最终导致其调节功能的失败。
Six different substitution mutations were identified in four different amino acid residues of antithrombin strand 1C and the polypeptide leading into strand 4B (F402S, F402C, F402L, A404T, N405K, and P407T), and are responsible for functional antithrombin deficiency in seven independently ascertained kindreds (Rosny, Torino, Maisons-Laffitte, Paris 3, La Rochelle, Budapest 5, and Oslo) affected by venous thromboembolic disease. In all seven families, variant antithrombins with heparin-binding abnormalities were detected by crossed immunoelectrophoresis, and in six of the kindreds there was a reduced antigen concentration of plasma antithrombin. Two of the variant antithrombins, Rosny and Torino, were purified by heparin-Sepharose and immunoaffinity chromatography, and shown to have greatly reduced heparin cofactor and progressive inhibitor activities in vitro. The defective interactions of these mutants with thrombin may result from proximity of s1C to the reactive site, while reduced circulating levels may be related to s1C proximity to highly conserved internal beta strands, which contain elements proposed to influence serpin turnover and intracellular degradation. In contrast, s1C is spatially distant to the positively charged surface which forms the heparin binding site of antithrombin; altered heparin binding properties of s1C variants may therefore reflect conformational linkage between the reactive site and heparin binding regions of the molecule. This work demonstrates that point mutations in and immediately adjacent to strand 1C have multiple, or pleiotropic, effects on this serpin, leading ultimately to failure of its regulatory function.