title: Direct interaction of endogenous Kv channels with syntaxin enhances exocytosis by neuroendocrine cells.
abstract: K(+) efflux through voltage-gated K(+) (Kv) channels can attenuate the release of neurotransmitters, neuropeptides and hormones by hyperpolarizing the membrane potential and attenuating Ca(2+) influx. Notably, direct interaction between Kv2.1 channels overexpressed in PC12 cells and syntaxin has recently been shown to facilitate dense core vesicle (DCV)-mediated release. Here, we focus on endogenous Kv2.1 channels and show that disruption of their interaction with native syntaxin after ATP-dependent priming of the vesicles by Kv2.1 syntaxin-binding peptides inhibits Ca(2+) -triggered exocytosis of DCVs from cracked PC12 cells in a specific and dose-dependent manner. The inhibition cannot simply be explained by the impairment of the interaction of syntaxin with its SNARE cognates. Thus, direct association between endogenous Kv2.1 and syntaxin enhances exocytosis and in combination with the Kv2.1 inhibitory effect to hyperpolarize the membrane potential, could contribute to the known activity dependence of DCV release in neuroendocrine cells and in dendrites where Kv2.1 commonly expresses and influences release.
authors.affiliation: Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel-Aviv University, Ramat-Aviv, Israel.
authors.forename: Dafna
authors.initials: D
authors.lastname: Singer-Lahat
authors.forename: Dodo
authors.initials: D
authors.lastname: Chikvashvili
authors.forename: Ilana
authors.initials: I
authors.lastname: Lotan
mesh_terms: D000818:Animals; D005089:Exocytosis; D009490:Neurosecretory Systems / Q000166:cytology / Q000378:metabolism*; D016716:PC12 Cells; D011485:Protein Binding; D050765:Qa-SNARE Proteins / Q000378:metabolism*; D051381:Rats; D051669:Shab Potassium Channels / Q000378:metabolism*
chemical_list: C496991:Kcnb1 protein, rat; D050765:Qa-SNARE Proteins; D051669:Shab Potassium Channels