Heiss S G, Cooper J A
Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110.
Biochemistry. 1991 Sep 10;30(36):8753-8. doi: 10.1021/bi00100a006.
Chicken muscle CapZ, a member of the capping protein family of actin-binding proteins, binds to the barbed end of actin filaments and nucleates actin polymerization. No regulation of the capping protein family has been described. We report that micelles of phosphatidylinositol 4,5-bisphosphate (PIP2) bind to CapZ and completely inhibit its ability to affect actin polymerization as measured by several independent assays. Higher concentrations of other anionic phospholipids also completely inhibit the activity of CapZ. Neutral phospholipids have no effect. Mixed vesicles of PIP2 with phosphatidylcholine or phosphatidylethanolamine also inhibit CapZ, but addition of Triton X-100 both prevents and reverses PIP2's inhibition of CapZ.
鸡肌肉中的帽蛋白（CapZ）是肌动蛋白结合蛋白帽蛋白家族的一员，它与肌动蛋白丝的尖端结合并引发肌动蛋白聚合。目前尚未发现对帽蛋白家族有调控作用的相关描述。我们报告称，磷脂酰肌醇4,5-二磷酸（PIP2）的微团与CapZ结合，并通过多种独立测定方法测量发现，其完全抑制了CapZ影响肌动蛋白聚合的能力。其他阴离子磷脂的较高浓度也能完全抑制CapZ的活性。中性磷脂则没有影响。PIP2与磷脂酰胆碱或磷脂酰乙醇胺的混合囊泡也能抑制CapZ，但加入 Triton X-100既能防止也能逆转PIP2对CapZ的抑制作用。
