title: Recombinant tandem of pore-domains in a Weakly Inward rectifying K+channel 2 (TWIK2) forms active lysosomal channels.
abstract: Recombinant TWIK2 channels produce weak basal background K+currents. Current amplitudes depend on the animal species the channels have been isolated from and on the heterologous system used for their re-expression. Here we show that this variability is due to a unique cellular trafficking. We identified three different sequence signals responsible for the preferential expression of TWIK2 in the Lamp1-positive lysosomal compartment. Sequential inactivation of tyrosine-based (Y308ASIP) and di-leucine-like (E266LILL and D282EDDQVDIL) trafficking motifs progressively abolishes the targeting of TWIK2 to lysosomes, and promotes its functional relocation at the plasma membrane. In addition, TWIK2 contains two N-glycosylation sites (N79AS and N85AS) on its luminal side, and glycosylation is necessary for expression in lysosomes. As shown by electrophysiology and electron microscopy, TWIK2 produces functional background K+currents in the endolysosomes, and its expression affects the number and mean size of the lysosomes. These results show that TWIK2 is expressed in lysosomes, further expanding the registry of ion channels expressed in these organelles.
authors.affiliation: Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, 660 Route des Lucioles, 06560, Valbonne, France.
authors.forename: Nicole
authors.initials: N
authors.lastname: Bobak
authors.affiliation: Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, 660 Route des Lucioles, 06560, Valbonne, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Feliciangeli
authors.affiliation: Center for Integrated Protein Science CIPS-M and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors.forename: Cheng-Chang
authors.initials: CC
authors.lastname: Chen
authors.affiliation: Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, 660 Route des Lucioles, 06560, Valbonne, France.
authors.forename: Ismail
authors.initials: I
authors.lastname: Ben Soussia
authors.affiliation: Department of Neurology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131, Mainz, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Bittner
authors.affiliation: Centre Commun de Microscopie Appliquée, Université Nice Sophia Antipolis, Nice, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Pagnotta
authors.affiliation: Department of Neurology, University of Münster, Albert-Schweizer Campus 1, 48149, Münster, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Ruck
authors.affiliation: Center for Integrated Protein Science CIPS-M and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Biel
authors.affiliation: Center for Integrated Protein Science CIPS-M and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wahl-Schott
authors.affiliation: Center for Integrated Protein Science CIPS-M and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Grimm
authors.affiliation: Department of Neurology, University of Münster, Albert-Schweizer Campus 1, 48149, Münster, Germany.
authors.forename: Sven G
authors.initials: SG
authors.lastname: Meuth
authors.affiliation: Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, LabEx ICST, 660 Route des Lucioles, 06560, Valbonne, France. lesage@ipmc.cnrs.fr.
authors.forename: Florian
authors.identifier: http://orcid.org/0000-0002-4406-7106
authors.initials: F
authors.lastname: Lesage
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004285:Dogs; D015870:Gene Expression; D057809:HEK293 Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D024683:Potassium Channels, Tandem Pore Domain / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D021381:Protein Transport; D051381:Rats; D011994:Recombinant Proteins
chemical_list: C492208:Kcnk6 protein, mouse; D024683:Potassium Channels, Tandem Pore Domain; D011994:Recombinant Proteins