TRPC7 is a receptor-operated DAG-activated channel in human keratinocytes
TRPC7 is a receptor-operated DAG-activated channel in human keratinocytes
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DOI：
10.1038/sj.jid.5700352
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发表时间：
2006-09-01
影响因子：
6.5
通讯作者：
Skryma, Roman
中科院分区：
文献类型：
--
作者：
Beck, Benjamin;Zholos, Alexander;Skryma, Roman
角质形成细胞中表达的毒蕈碱和嘌呤受体是细胞生长功能系统的重要组成部分。虽然这个过程的几个方面显然依赖于Ca 2+稳态，但对表皮受体刺激期间控制Ca 2+进入的机制知之甚少。我们采用膜片钳技术研究了卡巴胆碱（CCh）和三磷酸腺苷（ATP）在HaCaT人角质形成细胞的反应。这两种激动剂诱导的大电流介导的阳离子选择性通道约三倍渗透到Ca 2+比Na+，这表明它们在受体操作的Ca 2+进入中发挥重要作用。CCh和ATP诱导的电流被磷脂酶C（PLC）阻断剂1-[6-（[（17 β）-3-甲氧基雌甾-1，3，5（10）-三烯-17-基]氨基）己基]-1H-吡咯-2，5-二酮抑制。对PLC激活下游途径的研究表明，InsP（3）不影响激动剂反应。与此相反，1-油酰基-2-乙酰基-sn-甘油（OAG），1，2-二酰基甘油（DAG）的膜渗透性类似物，诱发类似的阳离子电流。这种作用似乎是直接的，因为蛋白激酶C的激活剂或抑制剂的作用相对较小。最后，瞬时受体电位典型7（TRPC 7）特异性敲低反义寡核苷酸导致ATP和CCh诱导的钙离子内流减少，以及OAG诱发的电流。我们的结论是，激活毒蕈碱和嘌呤受体通过一个共同的DAG依赖性连接打开Ca 2+渗透TRPC 7通道。
Muscarinic and purinergic receptors expressed in keratinocytes are an important part of a functional system for cell growth. While several aspects of this process are clearly dependent on Ca2+ homeostasis, less is known about the mechanisms controlling Ca2+ entry during epidermal receptor stimulation. We used patch-clamp technique to study responses to carbachol (CCh) and adenosine triphosphate (ATP) in HaCaT human keratinocytes. Both agonists induced large currents mediated by cation-selective channels about three times more permeable to Ca2+ than Na+, suggesting that they play an important role in receptor-operated Ca2+ entry. CCh- and ATP-induced currents were inhibited by 1-[6-([(17 beta)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino) hexyl]-1H-pyrrole-2,5-dione, a phospholipase C (PLC) blocker. Investigation of the pathways downstream of PLC activation revealed that InsP(3) did not affect the agonist responses. In contrast, 1-oleoyl-2-acetyl-sn-glycerol (OAG), a membrane-permeable analog of 1,2-diacylglycerol (DAG), evoked a similar cation current. This action appears to be direct, since the effects of activators or inhibitors of protein kinase C were comparatively small. Finally, transient receptor potential canonical 7 (TRPC7) specific knockdown by antisense oligonucleotides led to a decrease in ATP- and CCh-induced calcium entry, as well as OAG-evoked current. We concluded that activation of both muscarinic and purinergic receptors via a common DAG-dependent link opens Ca2+-permeable TRPC7 channels.