Bellagamba C, Hubaishy I, Bjorge J D, Fitzpatrick S L, Fujita D J, Waisman D M
Cell Regulation Research Group, Department of Medical Biochemistry, Calgary, Alberta T2N 4N1, Canada.
J Biol Chem. 1997 Feb 7;272(6):3195-9. doi: 10.1074/jbc.272.6.3195.
In the present article we have examined if the interaction of the Ca2+-binding protein, annexin II tetramer (AIIt) with the plasma membrane phospholipids or with the submembranous cytoskeleton, effects the accessibility of the tyrosine phosphorylation site of AIIt. In the presence of Ca2+, pp60(c-src) catalyzed the incorporation of 0.22 +/- 0.05 mol of phosphate/mol of AIIt (mean +/- S.D., n = 5). The Ca2+-dependent binding of AIIt to purified adrenal medulla plasma membrane or phosphatidylserine vesicles stimulated the pp60(c-src)-dependent phosphorylation of AIIt to 0.62 +/- 0.04 mol of phosphate/mol of AIIt (mean +/- S.D., n = 5) or 0.93 +/- 0.07 mol of phosphate/mol of AIIt (mean +/- S.D., n = 5), respectively. Phosphatidylserine- or phosphatidylinositol-containing vesicles but not vesicles composed of phosphatidylcholine or phosphatidylethanolamine, stimulated the phosphorylation of AIIt. In contrast, the binding of AIIt to F-actin resulted in the incorporation of only 0.04 +/- 0.04 mol of phosphate/mol of AIIt (mean +/- S.D., n = 5). These results suggest that the interaction of AIIt with plasma membrane and not the submembranous cytoskeleton, activates the tyrosine phosphorylation of AIIt by inducing a conformational change in the protein resulting in the enhanced exposure or accessibility of the tyrosine-phosphorylation site.
在本文中，我们研究了钙离子结合蛋白膜联蛋白II四聚体（AIIt）与质膜磷脂或膜下细胞骨架的相互作用是否会影响AIIt酪氨酸磷酸化位点的可及性。在钙离子存在的情况下，pp60（c-src）催化每摩尔AIIt掺入0.22±0.05摩尔磷酸（平均值±标准差，n = 5）。AIIt与纯化的肾上腺髓质质膜或磷脂酰丝氨酸囊泡的钙离子依赖性结合分别将pp60（c-src）依赖性的AIIt磷酸化提高到每摩尔AIIt掺入0.62±0.04摩尔磷酸（平均值±标准差，n = 5）或0.93±0.07摩尔磷酸（平均值±标准差，n = 5）。含磷脂酰丝氨酸或磷脂酰肌醇的囊泡而非由磷脂酰胆碱或磷脂酰乙醇胺组成的囊泡刺激了AIIt的磷酸化。相反，AIIt与F-肌动蛋白的结合导致每摩尔AIIt仅掺入0.04±0.04摩尔磷酸（平均值±标准差，n = 5）。这些结果表明，AIIt与质膜而非膜下细胞骨架的相互作用通过诱导蛋白质构象变化，导致酪氨酸磷酸化位点的暴露或可及性增强，从而激活AIIt的酪氨酸磷酸化。
