Stendahl O, Krause K H, Krischer J, Jerström P, Theler J M, Clark R A, Carpentier J L, Lew D P
Department of Medical Microbiology, Linköping University, Sweden.
Science. 1994 Sep 2;265(5177):1439-41. doi: 10.1126/science.8073285.
Subcellular gradients of cytosolic free Ca2+ concentration, [Ca2+]i, are thought to be critical for the localization of functional responses within a cell. A potential but previously unexplored mechanism for the generation of gradients of [Ca2+]i is the accumulation of Ca2+ stores at the site of Ca2+ action. The distribution of the Ca2+ store markers Ca(2+)-dependent adenosine triphosphatase and calreticulin was investigated in resting and phagocytosing human neutrophils. Both proteins showed an evenly distributed fine granular pattern in nonphagocytosing cells, but became markedly concentrated in the filamentous actin-rich cytoplasmic area around the ingested particle during phagocytosis. This redistribution began at early stages of phagocytosis and did not depend on an increase in [Ca2+]i. Thus, accumulation of Ca2+ stores in a restricted area of the cell may contribute to the generation of localized increases in [Ca2+]i.
胞质游离钙离子浓度（[Ca2+]i）的亚细胞梯度被认为对于细胞内功能反应的定位至关重要。一种潜在但此前未被探索的产生[Ca2+]i梯度的机制是Ca2+储存库在Ca2+作用位点的积累。在静息和吞噬状态的人类中性粒细胞中研究了Ca2+储存库标记物钙（2+）依赖性三磷酸腺苷酶和钙网蛋白的分布。在非吞噬细胞中，这两种蛋白质均呈现均匀分布的细颗粒模式，但在吞噬过程中，它们在摄入颗粒周围富含丝状肌动蛋白的细胞质区域显著浓缩。这种重新分布在吞噬作用的早期阶段就开始了，并且不依赖于[Ca2+]i的增加。因此，Ca2+储存库在细胞的受限区域中的积累可能有助于产生局部的[Ca2+]i升高。
