Capacity of human serum to depolymerize actin filaments.
Capacity of human serum to depolymerize actin filaments.
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DOI：
10.1182/blood.v70.2.524.bloodjournal702524
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发表时间：
1987-08
期刊：
影响因子：
20.3
通讯作者：
P. Janmey;S. Lind
中科院分区：
文献类型：
--
作者：
P. Janmey;S. Lind
人血解聚丝状肌动蛋白。肌动蛋白丝和单体与人血清的相互作用进行了研究，通过以下的动力学和程度的芘标记的F-肌动蛋白的解聚，并通过分析血清蛋白粘附固定化肌动蛋白单体。在生理Ca 2+浓度，解聚F-肌动蛋白的进行在两个阶段：快速相，由于直接切断丝的血浆凝溶胶蛋白，和缓慢相归因于肌动蛋白单体的结合维生素D结合蛋白（DBP）。在没有Ca 2+的情况下，仅观察到慢相。人血清可完全除去10 ~ 18 μ mol/L的肌动蛋白，其中约5 μ mol/L迅速发生。解聚可以通过凝溶胶蛋白和DBP的正常血清浓度来解释。纤维蛋白原和纤连蛋白在体外与肌动蛋白结合，对肌动蛋白解聚的动力学或程度没有贡献。亲和层析和功能测定的存在下的凝溶胶-肌动蛋白复合物表明，除了G-肌动蛋白的血清中的肌动蛋白-DBP复合物的优先形成的结果，但除了F-肌动蛋白的血清产生凝溶胶-肌动蛋白复合物和DBP-肌动蛋白复合物。肌动蛋白单体和聚合物与这两种血清蛋白的独特结合表明，从解聚细丝和从循环中清除单体的角度来看，它们在体内的协调作用最大化。
Human blood depolymerizes filamentous (F-)actin. The interaction of actin filaments and monomers with human serum was studied by following the kinetics and extent of the depolymerization of pyrene-labeled F-actin and by analysis of serum proteins adhering to immobilized actin monomers. In physiologic Ca2+ concentrations, the depolymerization of F-actin proceeds in two stages: a rapid phase, attributed to direct severing of filaments by plasma gelsolin, and a slow phase attributed to the binding of actin monomers to vitamin D-binding protein (DBP). Without Ca2+, only the slow phase is observed. Human serum can completely depolymerize 10 to 18 mumol/L of actin, of which approximately 5 mumol/L occurs rapidly. Depolymerization can be accounted for by the normal serum concentrations of gelsolin and DBP. Fibrin(ogen) and fibronectin, which bind actin in vitro, do not contribute to the kinetics or extent of its depolymerization. Affinity chromatography and functional assays for the presence of gelsolin-actin complexes show that addition of G-actin to serum results in preferential formation of actin-DBP complexes, but that addition of F-actin to serum produces both gelsolin-actin complexes and DBP-actin complexes. The distinctive binding of actin monomers and polymers to these two serum proteins suggests a means by which their coordinated actions are maximized in vivo, from the standpoint of depolymerizing filaments and clearing monomers from the circulation.