Tyrosine phosphorylation of human platelet plasma membrane Ca2+-ATPase in hypertension
Tyrosine phosphorylation of human platelet plasma membrane Ca2+-ATPase in hypertension
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DOI：
10.1161/01.hyp.35.1.103
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发表时间：
2000-01-01
期刊：
影响因子：
8.3
通讯作者：
Dean, WL
中科院分区：
文献类型：
--
作者：
Blankenship, KA;Dawson, CB;Dean, WL
高血压患者血小板细胞内Ca 2+增加。以前，我们证明了血小板质膜Ca 2 +-ATP酶（PMCA）活性与舒张压呈负相关，抑制这种Ca 2+泵可以解释高血压中胞浆Ca 2+的升高。最近，我们发现在凝血酶刺激的血小板聚集过程中，PMCA的酪氨酸残基被磷酸化，这种磷酸化导致PMCA活性的抑制。在目前的工作中，我们测试的假设，高血压患者的PMCA酪氨酸磷酸化可以解释所观察到的抑制钙泵。血小板从未经治疗的高血压和血压正常的志愿者中获得。从溶解的血小板中免疫沉淀PMCA，并通过用抗磷酸酪氨酸处理的免疫印迹的化学发光来定量酪氨酸磷酸化。通过剥离和用抗PMCA重新探测，在相同的免疫印迹上测量PMCA含量。磷酸化以每纳克PMCA的标准化磷酸酪氨酸化学发光（平均值+/-SE）报告。15名正常血压受试者的平均PMCA酪氨酸磷酸化为0.53+/-0.09，而8名高血压患者的平均值为1.82+/-0.25（P
Intracellular Ca2+ is increased in the platelets of hypertensive individuals. Previously, we demonstrated that platelet plasma membrane Ca2+-ATPase (PMCA) activity inversely correlates with diastolic blood pressure and that inhibition of this Ca2+ pump could explain the elevation of cytosolic Ca2+ in hypertension. More recently, we discovered that PMCA is phosphorylated on tyrosine residues during thrombin-stimulated platelet aggregation and that this phosphorylation causes inhibition of PMCA activity. In the present work, we tested the hypothesis that tyrosine phosphorylation of PMCA in hypertensive patients could account for the observed inhibition of the Ca2+ pump. Platelets were obtained from untreated hypertensive and normotensive volunteers. PMCA was immunoprecipitated from solubilized platelets, and tyrosine phosphorylation was quantified by chemiluminescence of immunoblots treated with anti-phosphotyrosine. PMCA content was measured on the same immunoblots by stripping and reprobing with anti-PMCA. Phosphorylation was reported as normalized phosphotyrosine chemiluminescence per nanogram PMCA (mean+/-SE), The average PMCA tyrosine phosphorylation for 15 normotensive subjects was 0.53+/-0.09, whereas the average for 8 hypertensive individuals was 1.82+/-0.25 (P