Abdelhaleem M M, Hatskelzon L, Dalal B I, Gerrard J M, Greenberg A H
Manitoba Institute of Cell Biology, Winnipeg, Canada.
J Immunol. 1991 Nov 1;147(9):3053-9.
A membrane glycoprotein of human platelet dense granules, called granulophysin, with serologic homology to synaptophysin has recently been identified. To determine if this protein was present in granulated leukocytes, we examined several cell types for the presence of the protein by indirect immunofluorescence. Antigranulophysin mAb staining was detected in a granular pattern in the cytoplasm of permeabilized IL-2-stimulated CD3+ peripheral lymphocytes, neutrophils, U937 monocytes, and mast cells. Immunohistochemistry of human lymph nodes showed cytoplasmic staining of macrophages, neutrophils, and some dendritic cells. Induction of granule exocytosis in granulated CD3+ lymphocytes after stimulation with PMA and calcium ionophore A23187 resulted in a redistribution of the reactive epitope from the cytoplasm to the plasma membrane. Subcellular fractions contained two peaks of reactivity; the first peak coincided with N-benzyloxycarbonyl-L-lysine thiobenzyl ester-esterase activity in dense granules whereas the second peak was present in lighter fractions. The affinity purified protein from both peaks was identical in Western blot analysis and had a molecular mass of 28 kDa under reducing conditions. The protein could only be solubilized in detergent suggesting that it was an integral membrane protein. We have named this protein leukophysin to differentiate it from the 40-kDa granulophysin of platelets. Monocytes contained a protein with identical m.w. to leukophysin, whereas a protein of a slightly higher m.w. was detected in neutrophils. We propose that leukophysin is a common granule membrane protein of leukocytes.
最近发现了一种人血小板致密颗粒的膜糖蛋白，称为颗粒膜蛋白，它与突触囊泡蛋白有血清学同源性。为了确定这种蛋白是否存在于颗粒白细胞中，我们通过间接免疫荧光检查了几种细胞类型中该蛋白的存在情况。在经白细胞介素-2刺激的CD3⁺外周淋巴细胞、中性粒细胞、U937单核细胞和肥大细胞的通透细胞质中，抗颗粒膜蛋白单克隆抗体染色呈颗粒状。人淋巴结的免疫组织化学显示巨噬细胞、中性粒细胞和一些树突状细胞的细胞质染色。用佛波酯和钙离子载体A23187刺激颗粒状CD3⁺淋巴细胞后，颗粒胞吐作用的诱导导致反应性表位从细胞质重新分布到质膜。亚细胞组分含有两个反应性峰值；第一个峰值与致密颗粒中的N-苄氧羰基-L-赖氨酸硫代苄酯酯酶活性一致，而第二个峰值存在于较轻的组分中。在蛋白质印迹分析中，从两个峰值纯化的亲和蛋白相同，在还原条件下分子量为28 kDa。该蛋白只能在去污剂中溶解，表明它是一种整合膜蛋白。我们将这种蛋白命名为白细胞膜蛋白，以将其与血小板的40 kDa颗粒膜蛋白区分开来。单核细胞含有一种分子量与白细胞膜蛋白相同的蛋白，而在中性粒细胞中检测到一种分子量略高的蛋白。我们认为白细胞膜蛋白是白细胞常见的颗粒膜蛋白。
