Haddad J G, Harper K D, Guoth M, Pietra G G, Sanger J W
Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104.
Proc Natl Acad Sci U S A. 1990 Feb;87(4):1381-5. doi: 10.1073/pnas.87.4.1381.
Two plasma proteins, vitamin D-binding protein (actin monomer sequestrant) and gelsolin (actin polymer severing), have been found in association with actin in plasma from ill humans and during experimental injury. In vitro, these are the only plasma proteins that display a high affinity for actin. We infused increasing amounts of globular actin intravenously to rats to evaluate its disposition in plasma and tissues. Intravascular filament formation, microthrombi, and endothelial injury were observed, especially in the pulmonary circulation. These pathological changes were not observed when the globular actin in the infusate had been preincubated with the vitamin D-binding protein in vitro. Complexes of actin with both proteins were found in the plasma, suggesting a saturable, plasma actin-binding system in vivo. Our findings suggest that in vivo saturation of these proteins' actin-binding capacities may serve as a paradigm for pulmonary vascular disorders seen during widespread tissue trauma and cell lysis.
在患病人类的血浆以及实验性损伤过程中，发现了两种血浆蛋白，即维生素D结合蛋白（肌动蛋白单体螯合剂）和凝溶胶蛋白（肌动蛋白聚合物切断剂）与肌动蛋白相关联。在体外，这是仅有的两种对肌动蛋白具有高亲和力的血浆蛋白。我们给大鼠静脉注射递增剂量的球状肌动蛋白，以评估其在血浆和组织中的处置情况。观察到血管内细丝形成、微血栓和内皮损伤，尤其是在肺循环中。当输注液中的球状肌动蛋白在体外与维生素D结合蛋白预孵育时，未观察到这些病理变化。在血浆中发现了肌动蛋白与这两种蛋白的复合物，表明体内存在一个可饱和的血浆肌动蛋白结合系统。我们的研究结果表明，这些蛋白的肌动蛋白结合能力在体内的饱和可能是广泛组织创伤和细胞裂解期间所见肺血管疾病的一个范例。
