title: Subunit-dependent axonal trafficking of distinct alpha heteromeric potassium channel complexes.
abstract: Voltage-gated potassium (Kv) channels are critical for neuronal excitability and are targeted to specific subcellular compartments to carry out their unique functions. While it is widely believed that Kv channels exist as heteromeric complexes in neurons, direct tests of the hypothesis that specific heteromeric channel populations display divergent spatial and temporal dynamics are limited. Using a bimolecular fluorescence complementation approach, we monitored the assembly and localization of cell surface channel complexes in living cells. While PSD95-mediated clustering was subunit independent, selective visualization of heteromeric Kv complexes in rat hippocampal neurons revealed subunit-dependent localization that was not predicted by analyzing individual subunits. Assembly of Kv1.1 with Kv1.4 prevented axonal localization but not surface expression, while inclusion of Kv1.2 imparted clustering at presynaptic sites and decreased channel mobility within the axon. This mechanism by which specific Kv channel subunits can act in a dominant manner to impose unique trafficking properties to heteromeric complexes extended to Shab-related family of Kv channels. When coexpressed, Kv2.1 and Kv2.2 heteromultimers did not aggregate in somatodendritic clusters observed with expression of Kv2.1 alone. These studies demonstrate selective axonal trafficking and surface localization of distinct Kv channels based on their subunit composition.
authors.affiliation: Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Jenkins
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: McIntyre
authors.forename: Lian
authors.initials: L
authors.lastname: Zhang
authors.forename: Arun
authors.initials: A
authors.lastname: Anantharam
authors.forename: Eileen D
authors.initials: ED
authors.lastname: Vesely
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Arendt
authors.forename: Cynthia J L
authors.initials: CJ
authors.lastname: Carruthers
authors.forename: Tom K
authors.initials: TK
authors.lastname: Kerppola
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Iñiguez-Lluhí
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Holz
authors.forename: Michael A
authors.initials: MA
authors.lastname: Sutton
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Martens
mesh_terms: D000818:Animals; D001370:Axonal Transport / Q000502:physiology*; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D005260:Female; D006624:Hippocampus / Q000378:metabolism / Q000502:physiology; D008297:Male; D008564:Membrane Potentials; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods; D021122:Protein Subunits / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology*; D051381:Rats; D051637:Shaker Superfamily of Potassium Channels / Q000378:metabolism*
chemical_list: D021122:Protein Subunits; D051637:Shaker Superfamily of Potassium Channels