Van Baelen H, Bouillon R, De Moor P
J Biol Chem. 1980 Mar 25;255(6):2270-2.
Actin, an ubiquitous highly conserved intracellular protein, and the serum vitamin D-binding protein (DBP) form tight 1:1 molar complexes in vitro. This interaction, which is not species-specific, explains the widespread occurrence of the 5-6 S protein responsible for the binding of 25-hydroxycholecalciferol in high speed supernatants of all nucleated tissues. Incubation of F-actin, the filamentous form of this protein, with DBP leads to depolymerization of the former. Actin, complexed with deoxyribonuclease I, retains its ability to bind DBP. Erythrocyte actin, prepared from red cell ghosts, also displays binding properties for DBP. The biological significance of this new interaction of actin is not yet understood.
肌动蛋白是一种普遍存在的高度保守的细胞内蛋白质，它与血清维生素D结合蛋白（DBP）在体外形成紧密的1:1摩尔复合物。这种相互作用不具有物种特异性，这解释了在所有有核组织的高速上清液中广泛存在的负责结合25-羟胆钙化醇的5-6S蛋白。这种蛋白质的丝状形式F-肌动蛋白与DBP孵育会导致前者解聚。与脱氧核糖核酸酶I复合的肌动蛋白保留了其结合DBP的能力。从红细胞膜制备的红细胞肌动蛋白也表现出对DBP的结合特性。肌动蛋白这种新相互作用的生物学意义尚不清楚。
