Distinct Ca2+-permeable cation currents are activated by internal Ca2+-store depletion in RBL-2H3 cells and human salivary gland cells, HSG and HSY
Distinct Ca2+-permeable cation currents are activated by internal Ca2+-store depletion in RBL-2H3 cells and human salivary gland cells, HSG and HSY
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DOI：
10.1007/s00232-004-0698-3
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发表时间：
2004-07-15
影响因子：
2.4
通讯作者：
Ambudkar, IS
中科院分区：
文献类型：
--
作者：
Liu, X;Groschner, K;Ambudkar, IS
钙池操纵的Ca 2+内流存在于所有细胞中，被认为是通过钙池操纵的阳离子通道（SOC）介导的。SOC的分子基础，以及这些通道可能的异质性，仍然是一个有争议的问题。本文比较了人颌下腺细胞（HSG）和人腮腺细胞（HSY）的SOC电流（I-SOC）和RBL细胞的I-CRAC（Ca ~（2+）释放激活的Ca ~（2+）电流）的特性。在所有三种细胞类型中，IP 3或毒胡萝卜素激活的阳离子通道导致内部Ca 2+储存耗尽。1 μ M Gd 3+阻断所有细胞的通道活性。洗脱Gd 3+诱导HSY和HSG部分恢复，但RBL细胞不。2-APB可逆地抑制所有细胞的通道。在RBL细胞中，E-rev（Ca）> + 90 mV，E-rev（Na）=+60 mV，呈强烈的内向整流。HSG细胞中的I-SOC显示较弱的整流，E-rev（Ca）= +25 mV和L-rev（Na）=+10 mV。HSY细胞显示线性电流，E-rev =+5mV，这在含Ca 2+或Na+的培养基中相似。pCa/pNa> 500、40和4.6，而pCs /pNa为0。1，1，和1。3，分别用于RBL、HSG和HSY细胞。用RBL和HSG细胞而不是HSY细胞获得了Ca 2 + /Na+渗透的异常摩尔分数行为的证据。此外，在浴中用Ca（2+）+ Na+或Na+的通道失活在三种细胞类型中是不同的。总之，这些数据表明，不同的存储依赖性阳离子电流刺激RBL，HSG，和HSY细胞。重要的是，这些数据表明这些通道的分子异质性和可能的细胞特异性功能差异。
Store-operated Ca2+ influx, suggested to be mediated via store-operated cation channel (SOC), is present in all cells. The molecular basis of SOC, and possible heterogeneity of these channels, are still a matter of controversy. Here we have compared the properties of SOC currents (I-SOC) in human sub-mandibular glands cells (HSG) and human parotid gland cells (HSY) with I-CRAC (Ca2+ release-activated Ca2+ current) in RBL cells. Internal Ca2+ store-depletion with IP3 or thapsigargin activated cation channels in all three cell types. 1 muM Gd3+ blocked channel activity in all cells. Washout of Gd3+ induced partial recovery in HSY and HSG but not RBL cells. 2-APB reversibly inhibited the channels in all cells. in RBL cells displayed strong inward rectification with E-rev(Ca) = > + 90 mV and E-rev (Na) = +60 mV. I-SOC in HSG cells showed weaker rectification with E-rev(Ca) = +25 mV and L-rev (Na) + 10 mV. HSY cells displayed a linear current with E-rev = + 5 mV, which was similar in Ca2+_ or Na+-containing medium. pCa/pNa was > 500, 40, and 4.6 while pCs /pNa was 0. 1, 1, and 1. 3, for RBL, HSG, and HSY cells, respectively. Evidence for anomalous mole fraction behavior of Ca2+ /Na+ permeation was obtained with RBL and HSG cells but not HSY cells. Additionally, channel inactivation with Ca (2+) + Na+ or Na+ in the bath was different in the three cell types. In aggregate, these data demonstrate that distinct store-dependent cation currents are stimulated in RBL, HSG, and HSY cells. Importantly, these data suggest a molecular heterogeneity, and possibly cell-specific differences in the function, of these channels.