A novel mechanism of modulation of hyperpolarization-activated cyclic nucleotide-gated channels by Src kinase.
نویسندگان
چکیده
Hyperpolarization-activated cyclic nucleotide-gated channels (HCN1-4) play a crucial role in the regulation of cell excitability. Importantly, they contribute to spontaneous rhythmic activity in brain and heart. HCN channels are principally activated by membrane hyperpolarization and binding of cAMP. Here, we identify tyrosine phosphorylation by Src kinase as another mechanism affecting channel gating. Inhibition of Src by specific blockers slowed down activation kinetics of native and heterologously expressed HCN channels. The same effect on HCN channel activation was observed in cells cotransfected with a dominant-negative Src mutant. Immunoprecipitation demonstrated that Src binds to and phosphorylates native and heterologously expressed HCN2. Src interacts via its SH3 domain with a sequence of HCN2 encompassing part of the C-linker and the cyclic nucleotide binding domain. We identified a highly conserved tyrosine residue in the C-linker of HCN channels (Tyr476 in HCN2) that confers modulation by Src. Replacement of this tyrosine by phenylalanine in HCN2 or HCN4 abolished sensitivity to Src inhibitors. Mass spectrometry confirmed that Tyr476 is phosphorylated by Src. Our results have functional implications for HCN channel gating. Furthermore, they indicate that tyrosine phosphorylation contributes in vivo to the fine tuning of HCN channel activity.
منابع مشابه
p38 mitogen-activated protein kinase: a novel modulator of hyperpolarization-activated cyclic nucleotide-gated channels and neuronal excitability.
متن کامل
Src tyrosine kinase alters gating of hyperpolarization-activated HCN4 pacemaker channel through Tyr531.
We recently discovered that the constitutively active Src tyrosine kinase can enhance hyperpolarization-activated, cyclic nucleotide-gated (HCN) 4 channel activity by binding to the channel protein. To investigate the mechanism of modulation by Src of HCN channels, we studied the effects of a selective inhibitor of Src tyrosine kinase, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimi...
متن کاملAn inward current induced by a putative cyclic nucleotide-gated channel in rat cerebellar Purkinje neurons
The roles of cyclic nucleotide-gated (CNG) channels in sensory transduction have long been recognized. More recent studies found that CNG channels are distributed in multiple brain regions involved in memory and learning, including the cortex, hippocampus and cerebellum. These findings suggest that their functions are not limited to sensory perception, but also to neuronal plasticity phenomena,...
متن کاملAn inward current induced by a putative cyclic nucleotide-gated channel in rat cerebellar Purkinje neurons
The roles of cyclic nucleotide-gated (CNG) channels in sensory transduction have long been recognized. More recent studies found that CNG channels are distributed in multiple brain regions involved in memory and learning, including the cortex, hippocampus and cerebellum. These findings suggest that their functions are not limited to sensory perception, but also to neuronal plasticity phenomena,...
متن کاملModulation of h-channels in hippocampal pyramidal neurons by p38 mitogen-activated protein kinase.
Hyperpolarization-activated cyclic nucleotide-gated ion channels (h-channels; I(h); HCN) modulate intrinsic excitability in hippocampal and neocortical pyramidal neurons, among others. Whereas I(h) mediated by the HCN2 isoform is regulated by cAMP, there is little known about kinase modulation of I(h), especially for the HCN1 isoform predominant in pyramidal neurons. We used a computational met...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of biological chemistry
دوره 280 40 شماره
صفحات -
تاریخ انتشار 2005