title: Large conductance voltage- and Ca2+-gated potassium (BK) channel β4 subunit influences sensitivity and tolerance to alcohol by altering its response to kinases.
abstract: Tolerance is a well described component of alcohol abuse and addiction. The large conductance voltage- and Ca(2+)-gated potassium channel (BK) has been very useful for studying molecular tolerance. The influence of association with the β4 subunit can be observed at the level of individual channels, action potentials in brain slices, and finally, drinking behavior in the mouse. Previously, we showed that 50 mm alcohol increases both α and αβ4 BK channel open probability, but only α BK develops acute tolerance to this effect. Currently, we explore the possibility that the influence of the β4 subunit on tolerance may result from a striking effect of β4 on kinase modulation of the BK channel. We examine the influence of the β4 subunit on PKA, CaMKII, and phosphatase modulation of channel activity, and on molecular tolerance to alcohol. We record from human BK channels heterologously expressed in HEK 293 cells composed of its core subunit, α alone (Insertless), or co-expressed with the β4 BK auxiliary subunit, as well as, acutely dissociated nucleus accumbens neurons using the cell-attached patch clamp configuration. Our results indicate that BK channels are strongly modulated by activation of specific kinases (PKA and CaMKII) and phosphatases. The presence of the β4 subunit greatly influences this modulation, allowing a variety of outcomes for BK channel activity in response to acute alcohol.
authors.affiliation: the Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico 00901.
authors.forename: Cristina
authors.initials: C
authors.lastname: Velázquez-Marrero
authors.affiliation: the Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico 00901.
authors.forename: Garrett E
authors.initials: GE
authors.lastname: Seale
authors.affiliation: the Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico 00901 steven.treistman@upr.edu.
authors.forename: Steven N
authors.initials: SN
authors.lastname: Treistman
authors.affiliation: From the Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, Massachusetts 01604 and Gilles.Martin@Umassmed.edu.
authors.forename: Gilles E
authors.initials: GE
authors.lastname: Martin
mesh_terms: D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D018999:Charybdotoxin / Q000737:chemistry; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004594:Electrophysiology; D000431:Ethanol / Q000737:chemistry*; D057809:HEK293 Cells; D006801:Humans; D051038:Large-Conductance Calcium-Activated Potassium Channel beta Subunits / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D009714:Nucleus Accumbens / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D011188:Potassium / Q000378:metabolism; D013997:Time Factors
chemical_list: C410183:KCNMB4 protein, human; D051038:Large-Conductance Calcium-Activated Potassium Channel beta Subunits; D009419:Nerve Tissue Proteins; D018999:Charybdotoxin; D000431:Ethanol; D017868:Cyclic AMP-Dependent Protein Kinases; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D010744:Phosphoric Monoester Hydrolases; D011188:Potassium
keywords: Alcohol; Neuron; Phosphorylation; Potassium Channel; Tolerance