Subunit-specific modulation of KCNQ potassium channels by Src tyrosine kinase.
نویسندگان
چکیده
We studied regulation by c-Src tyrosine kinase (Src) of KCNQ1-5 channels heterologously expressed in Chinese hamster ovary (CHO) cells and of native M current in rat sympathetic neurons. Using whole-cell patch clamp, we found that Src modulates currents from KCNQ3, KCNQ4, and KCNQ5 homomultimers, KCNQ2/3 heteromultimers and native M current, but not currents from KCNQ1 or KCNQ2 homomultimers. Src overexpression had two effects: a decrease of current amplitude (4- to 15-fold for cloned channels and approximately 3-fold for M current) and a slowing of activation kinetics by 2-fold. Both Src actions were mostly reversed by bath application of the Src inhibitors erbstatin (20 microm) and PP2 (200 nm), and mimicked by the tyrosine phosphatase inhibitor sodium vanadate (100 microm). Immunoprecipitation and immunoblot analysis showed Src-dependent phosphotyrosine signals associated with KCNQ3, KCNQ4, and KCNQ5 but not with KCNQ1 or KCNQ2 that may be tyrosine phosphorylation of the channel subunits. Expression of a dominant negative Src that cannot phosphorylate substrates had no effect on the current and did not induce phosphotyrosine signals associated with KCNQ3-5 subunits, further indicating that Src actions on KCNQ currents are mediated by tyrosine phosphorylation. Immunostaining and confocal analysis showed no effect of Src overexpression on the abundance of KCNQ3 protein in CHO cells. Finally, experiments using cloned KCNQ2/3 channels, Src and M(1) muscarinic receptors, and sympathetic neurons demonstrated that the actions on KCNQ channels by Src and by muscarinic agonists use distinct mechanisms.
منابع مشابه
O3: Pharmacological Modulation of Thalamic KCNQ-Potassium Channels: Insight from Knock-out Mice
The channels belonging to the KCNQ gene family consist of 5 different subtypes, which assemble as pentameric channels. The KCNQ2-5 subunits are highly expressed in the ventrobasal thalamus (VB) where they function primarily as KCNQ2/3 heteromers. They underlie an outward potassium (K+)-current, called M-current (IM), which provides a hyperpolarizing drive, thus regulating neuronal excitability....
متن کاملPhosphorylation-dependent and phosphorylation-independent modes of modulation of shaker family voltage-gated potassium channels by SRC family protein tyrosine kinases.
Modulation of voltage-gated potassium (Kv) channels by protein phosphorylation plays an essential role in the regulation of the membrane properties of cells. Protein-protein binding domains, such as Src homology 3 (SH3) domains, direct ion channel modulation by coupling the channels with intracellular signaling enzymes. The conventional view is that protein kinase binding to ion channels leads ...
متن کاملSimultaneous binding of two protein kinases to a calcium-dependent potassium channel.
Large-conductance calcium-dependent potassium channels are subject to modulation by protein kinases, phosphatases, and other signaling proteins, and it has been inferred from electrophysiological experiments that signaling proteins sometimes can be intimately associated with these channels in a regulatory complex. We show here that endogenous protein kinase activity coimmunoprecipitates with bo...
متن کاملThe calcium-dependent activity of large-conductance, calcium-activated K+ channels is enhanced by Pyk2- and Hck-induced tyrosine phosphorylation.
Recent results showing that large-conductance, calcium-activated K(+) (BK(Ca)) channels undergo direct tyrosine phosphorylation in the presence of c-Src tyrosine kinase have suggested the involvement of these channels in Src-mediated signaling pathways. Given the important role for c-Src in integrin-mediated signal transduction, we have examined the potential regulation of BK(Ca) channels by pr...
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 neuroscience : the official journal of the Society for Neuroscience
دوره 23 1 شماره
صفحات -
تاریخ انتشار 2003