Epidermal growth factor induces tyrosine phosphorylation, membrane insertion, and activation of transient receptor potential channel 4
Epidermal growth factor induces tyrosine phosphorylation, membrane insertion, and activation of transient receptor potential channel 4
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DOI：
10.1074/jbc.m503646200
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发表时间：
2005-11-11
影响因子：
4.8
通讯作者：
Van Helden, DF
中科院分区：
文献类型：
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作者：
Odell, AF;Scott, JL;Van Helden, DF
瞬时受体电位通道（trpc）家族的各种典型成员在受体刺激或Ca2+储存耗尽后表现出增加的阳离子内流。TRP家族成员的酪氨酸磷酸化也导致通道活性增加；然而，这两件事之间的联系尚不清楚。我们报道了在COS-7细胞的表皮生长因子（EGF）受体刺激下，人类TRPC4 (hTRPC4) C端的两个酪氨酸残基tyr959和tyr972被磷酸化。这种磷酸化是由Src家族酪氨酸激酶（STKs）介导的，其中Fyn似乎是显性激酶。此外，EGF受体刺激诱导hTRPC4胞外插入质膜依赖于STKs的活性，并伴随着磷酸化依赖性的hTRPC4与Na+/H+交换剂调节因子的关联增加。此外，当Tyr-959和Tyr-972突变为苯丙氨酸时，这种易位和关联存在缺陷。值得注意的是，在天然COS-7细胞和表达htrpc4的HEK293细胞中，STKs的抑制伴随着Ca2+内流的减少，表达y995f /Y972F突变体的细胞表现出减少的EGF反应。这些发现首次证明了磷酸化调节TRPC通道功能的机制。
Various members of the canonical family of transient receptor potential channels (TRPCs) exhibit increased cation influx following receptor stimulation or Ca2+ store depletion. Tyrosine phosphorylation of TRP family members also results in increased channel activity; however, the link between the two events is unclear. We report that two tyrosine residues in the C terminus of human TRPC4 (hTRPC4), Tyr-959 and Tyr-972, are phosphorylated following epidermal growth factor (EGF) receptor stimulation of COS-7 cells. This phosphorylation was mediated by Src family tyrosine kinases (STKs), with Fyn appearing to be the dominant kinase. In addition, EGF receptor stimulation induced the exocytotic insertion of hTRPC4 into the plasma membrane dependent on the activity of STKs and was accompanied by a phosphorylation-dependent increase in the association of hTRPC4 with Na+/H+ exchanger regulatory factor. Furthermore, this translocation and association was defective upon mutation of Tyr-959 and Tyr-972 to phenylalanine. Significantly, inhibition of STKs was concomitant with a reduction in Ca2+ influx in both native COS-7 cells and hTRPC4-expressing HEK293 cells, with cells expressing the Y959F/Y972F mutant exhibiting a reduced EGF response. These findings represent the first demonstration of a mechanism for phosphorylation to modulate TRPC channel function.