title: Stimulation of Slack K(+) Channels Alters Mass at the Plasma Membrane by Triggering Dissociation of a Phosphatase-Regulatory Complex.
abstract: Human mutations in the cytoplasmic C-terminal domain of Slack sodium-activated potassium (KNa) channels result in childhood epilepsy with severe intellectual disability. Slack currents can be increased by pharmacological activators or by phosphorylation of a Slack C-terminal residue by protein kinase C. Using an optical biosensor assay, we find that Slack channel stimulation in neurons or transfected cells produces loss of mass near the plasma membrane. Slack mutants associated with intellectual disability fail to trigger any change in mass. The loss of mass results from the dissociation of the protein phosphatase 1 (PP1) targeting protein, Phactr-1, from the channel. Phactr1 dissociation is specific to wild-type Slack channels and is not observed when related potassium channels are stimulated. Our findings suggest that Slack channels are coupled to cytoplasmic signaling pathways and that dysregulation of this coupling may trigger the aberrant intellectual development associated with specific childhood epilepsies.
authors.affiliation: Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Fleming
authors.affiliation: Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA.
authors.forename: Maile R
authors.initials: MR
authors.lastname: Brown
authors.affiliation: Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA.
authors.forename: Jack
authors.initials: J
authors.lastname: Kronengold
authors.affiliation: Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA.
authors.forename: Yalan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Jenkins
authors.affiliation: Department of Pediatric Neurology, Centre de Reference Epilepsies Rares, Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris (AP-HP), 75015 Paris, France.
authors.forename: Gulia
authors.initials: G
authors.lastname: Barcia
authors.affiliation: Department of Pediatric Neurology, Centre de Reference Epilepsies Rares, Hôpital Necker Enfants Malades, Assistance Publique-Hôpitaux de Paris (AP-HP), 75015 Paris, France.
authors.forename: Rima
authors.initials: R
authors.lastname: Nabbout
authors.affiliation: Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Bausch
authors.affiliation: Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Ruth
authors.affiliation: Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Lukowski
authors.affiliation: Department of Neurology, Yale School of Medicine, New Haven, CT 06520, USA.
authors.forename: Dhasakumar S
authors.initials: DS
authors.lastname: Navaratnam
authors.affiliation: Department of Pharmacology, Yale School of Medicine, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06520, USA. Electronic address: leonard.kaczmarek@yale.edu.
authors.forename: Leonard K
authors.initials: LK
authors.lastname: Kaczmarek
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015374:Biosensing Techniques; D001735:Bithionol / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D017136:Ion Transport / Q000187:drug effects; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000819:agonists / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D015221:Potassium Channels / Q000819:agonists / Q000235:genetics* / Q000378:metabolism; D000081033:Potassium Channels, Sodium-Activated; D061251:Primary Cell Culture; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D053778:Thiazolidines / Q000494:pharmacology; D014982:Xenopus laevis
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D001735:Bithionol; D019086:Bridged Bicyclo Compounds, Heterocyclic; D051860:Fragile X Messenger Ribonucleoprotein 1; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D000081033:Potassium Channels, Sodium-Activated; D034741:RNA, Small Interfering; D053778:Thiazolidines; C109916:CYFIP1 protein, human; C497683:FMR1 protein, human; C585122:KCNT1 protein, human; C570134:PHACTR1 protein, human; C037068:latrunculin B