Möhn H, Le Cabec V, Fischer S, Maridonneau-Parini I
LPTF, Centre National de la Recherche Scientifique, UPR 8221, Toulouse, France.
Biochem J. 1995 Jul 15;309 ( Pt 2)(Pt 2):657-65. doi: 10.1042/bj3090657.
The src-family protein-tyrosine kinase p59hck is mainly expressed in neutrophils; however, its functional role in these cells is unknown. Several other src-family members are localized on secretory vesicles and have been proposed to regulate intracellular traffic. We have established here the subcellular localization of p59hck in human neutrophils. Immunoblotting of subcellular fractions showed that approx. 60% of the p59hck per cell is localized on the secretory granules; the other 40% is distributed equally between non-granular membranes and the cytosol. Immunofluorescence of neutrophils and HL60 cells suggests that the p59hck-positive granules are azurophil granules. Granular p59hck is highly susceptible to degradation by an azurophil-granule proteinase. Different forms of p59hck occur in the three subcellular compartments: a 61 kDa form is mainly found in the granules, a 59 kDa form is predominant in the non-granular membranes, whereas cytosolic p59hck migrates as a doublet at 63 kDa. During the process of phagocytosis-linked degranulation, induced by serum-opsonized zymosan in neutrophils or HL60 cells, granular p59hck translocates towards the phagosome. The subcellular localization of p59hck suggests that the enzyme could be involved in the regulation of the degranulation process.
src家族蛋白酪氨酸激酶p59hck主要在中性粒细胞中表达；然而，其在这些细胞中的功能作用尚不清楚。其他几个src家族成员定位于分泌小泡，并被认为参与调节细胞内运输。我们在此确定了p59hck在人中性粒细胞中的亚细胞定位。亚细胞组分的免疫印迹显示，每个细胞中约60%的p59hck定位于分泌颗粒；另外40%均匀分布于非颗粒膜和胞质溶胶之间。中性粒细胞和HL60细胞的免疫荧光表明，p59hck阳性颗粒为嗜天青颗粒。颗粒状p59hck极易被嗜天青颗粒蛋白酶降解。p59hck在三个亚细胞区室中呈现不同形式：61 kDa的形式主要存在于颗粒中，59 kDa的形式在非颗粒膜中占主导，而胞质溶胶中的p59hck以63 kDa的双峰形式迁移。在血清调理酵母聚糖诱导的中性粒细胞或HL60细胞吞噬相关脱颗粒过程中，颗粒状p59hck向吞噬体转位。p59hck的亚细胞定位表明该酶可能参与脱颗粒过程的调节。
