title: Forward Transport of K2p3.1: mediation by 14-3-3 and COPI, modulation by p11.
abstract: Surface expression of the K(2P)3.1 two-pore domain potassium channel is regulated by phosphorylation-dependent binding of 14-3-3, leading to suppression of coatomer coat protein I (COPI)-mediated retention in endoplasmic reticulum (ER). Here, we investigate the nature of the macromolecular regulatory complexes that mediate forward and retrograde transport. We demonstrate that (i) the channel employs two separate but interacting COPI binding sites on the N- and C-termini; (ii) disrupting COPI binding to either site interferes with the ER retention; (iii) p11 and 14-3-3 do not interact on their own; (iv) p11 binding to the C-terminal retention motif is dependent on 14-3-3; and (v) p11 is coexpressed in only a subset of tissues with K(2P)3.1, while 14-3-3 expression is ubiquitous. We conclude that K(2P)3.1 forward transport requires 14-3-3 suppression of COPI binding, whereas p11 serves a modulatory role.
authors.affiliation: The Faculty of Life Sciences, The University of Manchester, 46 Grafton Street, Manchester, M13 9NT, UK. ita.o'kelly-2@manchester.ac.uk
authors.forename: Ita
authors.initials: I
authors.lastname: O'Kelly
authors.forename: Steve A N
authors.initials: SA
authors.lastname: Goldstein
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D000818:Animals; D017306:Annexin A2 / Q000378:metabolism*; D001665:Binding Sites; D020755:Coat Protein Complex I / Q000378:metabolism*; D004594:Electrophysiology; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000502:physiology; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels / Q000378:metabolism*; D047468:Immunoprecipitation; D009928:Organ Specificity; D010446:Peptide Fragments / Q000378:metabolism; D010766:Phosphorylation; D024683:Potassium Channels, Tandem Pore Domain / Q000378:metabolism*; D025941:Protein Interaction Mapping; D021381:Protein Transport; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism*; D014982:Xenopus laevis; D000099248:S100 Calcium Binding Protein A10
chemical_list: D048948:14-3-3 Proteins; D017306:Annexin A2; D020755:Coat Protein Complex I; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D010446:Peptide Fragments; D024683:Potassium Channels, Tandem Pore Domain; D011993:Recombinant Fusion Proteins; D009418:S100 Proteins; D000099248:S100 Calcium Binding Protein A10