A PLATELET ALPHA GRANULE MEMBRANE-PROTEIN THAT IS ASSOCIATED WITH THE PLASMA-MEMBRANE AFTER ACTIVATION - CHARACTERIZATION AND SUBCELLULAR-LOCALIZATION OF PLATELET ACTIVATION-DEPENDENT GRANULE-EXTERNAL MEMBRANE-PROTEIN
A PLATELET ALPHA GRANULE MEMBRANE-PROTEIN THAT IS ASSOCIATED WITH THE PLASMA-MEMBRANE AFTER ACTIVATION - CHARACTERIZATION AND SUBCELLULAR-LOCALIZATION OF PLATELET ACTIVATION-DEPENDENT GRANULE-EXTERNAL MEMBRANE-PROTEIN
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DOI：
10.1172/jci112542
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发表时间：
1986-07-01
影响因子：
15.9
通讯作者：
FURIE, B
中科院分区：
文献类型：
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作者：
BERMAN, CL;YEO, EL;FURIE, B
我们已经鉴定并纯化了一种血小板整合膜蛋白（140，000 molwt），使用对活化血小板特异的KC 4单克隆抗体，其在静息血小板内部，但暴露在活化血小板上（Hsu-Lin S. C.的方法，C. L.，伯曼，B。C. Furie，D. August和B Furie，1984，J. Biol. Chem. 259：9121-9126）。该蛋白在血小板表面的表达是分泌依赖性的。这种蛋白质被命名为血小板活化依赖性颗粒外膜（PADGEM）蛋白。PADGEM蛋白不同于静息血小板的表面糖蛋白，但与S12抗原GMP-140相同。使用免疫荧光染色，静息血小板不能用KC 4抗体对PADGEM蛋白染色，但透化后显示细胞内部的点状染色。凝血酶刺激的完整血小板染色的外周边缘图案，从而证明了从内部位置到细胞表面的PADGEM蛋白的易位。在不同凝血酶浓度下血小板表面PADGEM蛋白表达与α颗粒释放相关，如通过血小板因子4的分泌所测量。通过静息血小板的氮空化，然后通过甲泛葡胺密度梯度离心，提供了PADGEM蛋白的α颗粒定位的进一步证据; PADGEM蛋白与血小板因子4共分布。使用免疫电子显微镜，蛋白质被定位到α颗粒在冷冻切片的静息血小板标记兔抗PADGEM蛋白抗体，而在凝血酶活化的血小板，质膜被标记。这些研究表明，PADGEM蛋白是静息血小板α颗粒膜的组分，并在活化和分泌后掺入质膜。
We have identified and purified a platelet integral membrane protein (140,000 mol wt), using the KC4 monoclonal antibody specific for activated platelets, that is internal in resting platelets but exposed on activated platelets (Hsu-Lin S.-C., C. L., Berman, B. C. Furie, D. August, and B Furie, 1984, J. Biol. Chem. 259: 9121-9126.). The expression of the protein on the platelet surface is secretion-dependent. This protein has been named platelet activation-dependent granule-external membrane (PADGEM) protein. PADGEM protein is distinct from the surface glycoproteins of resting platelets, but identical to the S12 antigen, GMP-140. Using immunofluorescent staining, resting platelets failed to stain for PADGEM protein with the KC4 antibody, but after permeabilization showed a punctate staining of the cell interior. Thrombin-stimulated intact platelets stained with a peripheral rim pattern thus demonstrating the translocation of PADGEM protein from an internal location to the cell surface. PADGEM protein expression on the platelet surface at varying thrombin concentrations correlated with alpha granule release, as measured by the secretion of platelet factor 4. Further evidence for an alpha granule localization of PADGEM protein was provided by nitrogen cavitation of resting platelets followed by metrizamide density gradient centrifugation; PADGEM protein codistributed with platelet factor 4. Using immunoelectron microscopy, the protein was localized to the alpha granule in frozen ultrathin sections of resting platelets labeled using rabbit anti-PADGEM protein antibodies, whereas in thrombin-activated platelets, the plasma membrane was labeled. These studies indicate that PADGEM protein is a component of the alpha granule membrane of resting platelets and is incorporated into the plasma membrane upon activation and secretion.