Regulation of Cytoplasmic pH in Osteoclasts
Regulation of Cytoplasmic pH in Osteoclasts
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破骨细胞细胞质 pH 值的调节
DOI：
10.1074/jbc.270.5.2203
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
S. Grinstein
中科院分区：
文献类型：
--
作者：
T. Nordström;O. Rotstein;Robert Romanek;S. Asotra;J. Heersche;M. Manolson;G. Brisseau;S. Grinstein
破骨细胞通过位于褶皱边缘的液泡型质子泵将质子分泌到细胞外吸收区来吸收骨。本研究旨在评估质子泵是否也有助于细胞内pH调节。采用荧光成像、分光光度法和电生理学方法对体外培养兔破骨细胞的pH调节机制进行了研究。单个破骨细胞培养在玻璃片上，并负载了一个pH敏感的指示剂，在名义上没有HCO3的溶液中测量了荧光。当悬浮在富钠的培养液中时，细胞主要通过对阿米洛利敏感的Na/H逆向转运体从急性酸负荷中恢复。但在无钠条件下，以钾为代用品时，恢复速度也较快。对巴菲罗星敏感的空泡型泵对pH调节的贡献很小，没有发现K/H交换的证据。相反，在高K介质中，pH的恢复很大程度上归因于锌敏感的质子传导途径。通过膜片钳全细胞结构的破骨细胞来分析这种电导的特性。去极化脉冲引起缓慢发展的外向电流和伴随而来的胞浆碱化。离子置换实验中反转电位的测定表明，该电流是由于H(当量)跨膜转移而产生的。降低pH可显著刺激H电流，这与细胞内酸化时传导通路的动态平衡作用一致。这些结果表明，液泡型质子泵对从细胞内酸负荷中恢复细胞质pH的贡献最小。相反，这些数据表明破骨细胞的质膜上存在对pH和膜电位敏感的H电导。这种电导可能有助于骨吸收过程中电荷和酸当量的转移和/或破骨细胞产生活性氧中间体。
Osteoclasts resorb bone by secreting protons into an extracellular resorption zone through vacuolar-type proton pumps located in the ruffled border. The present study was undertaken to evaluate whether proton pumps also contribute to intracellular pH (pH) regulation. Fluorescence imaging and photometry, and electrophysiological methods were used to characterize the mechanisms of pH regulation in isolated rabbit osteoclasts. The fluorescence of single osteoclasts cultured on glass coverslips and loaded with a pH-sensitive indicator was measured in nominally HCO3-free solutions. When suspended in Na-rich medium, the cells recovered from an acute acid load primarily by means of an amiloride-sensitive Na/H antiporter. However, rapid recovery was also observed in Na-free medium when K was used as the substitute. Bafilomycin-sensitive, vacuolar-type pumps were found to contribute marginally to pH regulation and no evidence was found for K/H exchange. In contrast, pH recovery in high K medium was largely attributed to a Zn-sensitive proton conductive pathway. The properties of this conductance were analyzed by patch-clamping osteoclasts in the whole-cell configuration. Depolarizing pulses induced a slowly developing outward current and a concomitant cytosolic alkalinization. Determination of the reversal potential during ion substitution experiments indicated that the current was due to H (equivalent) translocation across the membrane. The H current was greatly stimulated by reducing pH, consistent with a homeostatic role of the conductive pathway during intracellular acidosis. These results suggest that vacuolar-type proton pumps contribute minimally to the recovery of cytoplasmic pH from intracellular acid loads. Instead, the data indicate the presence of a pH- and membrane potential-sensitive H conductance in the plasma membrane of osteoclasts. This conductance may contribute to translocation of charges and acid equivalents during bone resorption and/or generation of reactive oxygen intermediates by osteoclasts.
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DOI：
10.1152/ajpcell.1987.253.1.c90
发表时间：
1987-07
期刊：
The American journal of physiology
影响因子：
--
作者：
P. Hofmann;F. Fuchs
通讯作者：
P. Hofmann;F. Fuchs
来自哺乳动物肾脏的液泡 H()-ATP 酶的胞质抑制剂。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Zhang,K;Wang,ZQ;Gluck,S
通讯作者：
Gluck,S
影响因子：
56.9
作者：
BLAIR, HC;TEITELBAUM, SL;GLUCK, S
通讯作者：
GLUCK, S
网格蛋白包被的囊泡质子泵的蛋白质激活剂的分离。
DOI：
--
发表时间：
1993
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Xie,XS;Crider,BP;Stone,DK
通讯作者：
Stone,DK
影响因子：
15.9
作者：
TETI, A;BLAIR, HC;SCHLESINGER, PH
通讯作者：
SCHLESINGER, PH