GVI 型磷酯酶 A2 在鞘氨醇-1-磷酸刺激 TRPC5 阳离子通道中的作用。

GVI phospholipase A2 role in the stimulatory effect of sphingosine-1-phosphate on TRPC5 cationic channels.

机构信息

Multidisciplinary Cardiovascular Research Centre and the Institute of Membrane & Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.

出版信息

Cell Calcium. 2011 Oct;50(4):343-50. doi: 10.1016/j.ceca.2011.06.003. Epub 2011 Jul 13.

DOI:10.1016/j.ceca.2011.06.003

PMID:21742378

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC3195672/

Abstract

The Transient Receptor Potential Canonical 5 (TRPC5) protein forms calcium-permeable cationic channels that are stimulated by G protein-coupled receptor agonists. The signaling pathways of such agonist effects are poorly understood. Here we investigated the potential for involvement of lysophosphatidylcholine (LPC) and arachidonic acid generated by group 6 (GVI) phospholipase A2 (PLA2) enzymes, focusing on stimulation of TRPC5 by sphingosine-1-phosphate (S1P) which acts via a pertussis toxin-sensitive (Gi/o protein) pathway without Ca2+-release. Experiments were on HEK 293 cells containing conditional expression of human TRPC5. Channel activity was recorded using an intracellular calcium indicator or whole-cell patch-clamp and PLA2 activity was detected using 3H-arachidonic acid. S1P stimulated PLA2 and TRPC5 activities. Both effects were suppressed by the GVI PLA2 inhibitor bromoenol lactone. Knock-down of GVI PLA2 by RNA interference suppressed channel activity evoked by S1P whereas activity evoked by the direct channel stimulator LPC was unaffected. Arachidonic acid did not stimulate the channels. Prior exposure of channels to LPC but not arachidonic acid suppressed channel activity evoked by S1P but not gadolinium, a putative direct stimulator of the channels. The data suggest roles of LPC and GVI PLA2 in S1P-evoked TRPC5 activity.

摘要

瞬时受体电位经典型 5（TRPC5）蛋白形成钙通透性阳离子通道，受 G 蛋白偶联受体激动剂刺激。此类激动剂作用的信号通路知之甚少。在此，我们研究了 6 组（GVI）磷脂酶 A2（PLA2）酶产生的溶血磷脂酰胆碱（LPC）和花生四烯酸（由 GVI PLA2 酶产生）潜在参与的可能性，重点研究了通过鞘氨醇-1-磷酸（S1P）刺激 TRPC5，S1P 通过百日咳毒素敏感（Gi/o 蛋白）途径发挥作用，不伴有 Ca2+释放。实验在包含人源 TRPC5 条件表达的 HEK 293 细胞上进行。使用细胞内钙指示剂或全细胞膜片钳记录通道活性，并用 3H-花生四烯酸检测 PLA2 活性。S1P 刺激 PLA2 和 TRPC5 活性。这两种作用均被 GVI PLA2 抑制剂溴烯醇内酯抑制。RNA 干扰敲低 GVI PLA2 可抑制 S1P 诱发的通道活性，而直接通道刺激物 LPC 诱发的活性不受影响。花生四烯酸不能刺激通道。通道预先暴露于 LPC 而不是花生四烯酸可抑制 S1P 诱发的通道活性，但不抑制钆，钆是一种假定的通道直接刺激物。数据表明 LPC 和 GVI PLA2 在 S1P 诱发的 TRPC5 活性中发挥作用。