title: The sorting of a small potassium channel in mammalian cells can be shifted between mitochondria and plasma membrane.
abstract: The two small and similar viral K(+) channels Kcv and Kesv are sorted in mammalian cells and yeast to different destinations. Analysis of the sorting pathways shows that Kcv is trafficking via the secretory pathway to the plasma membrane, while Kesv is inserted via the TIM/TOM complex to the inner membrane of mitochondria. Studies with Kesv mutants show that an N-terminal mitochondrial targeting sequence in this channel is neither necessary nor sufficient for sorting of Kesv the mitochondria. Instead the sorting of Kesv can be redirected from the mitochondria to the plasma membrane by an insertion of ≥2 amino acids in a position sensitive manner into the C-terminal transmembrane domain (TMD2) of this channel. The available data advocate the presence of a C-terminal sorting signal in TMD2 of Kesv channel, which is presumably not determined by the length of this domain.
authors.affiliation: Plant Membrane Biophysics, TU Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
authors.forename: Charlotte
authors.initials: C
authors.lastname: von Charpuis
authors.affiliation: Plant Membrane Biophysics, TU Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Meckel
authors.affiliation: Department of Biology and CNR IBF-Mi, and Istituto Nazionale di Fisica della Materia, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Moroni
authors.affiliation: Plant Membrane Biophysics, TU Darmstadt, Schnittspahnstrasse 3, 64287 Darmstadt, Germany. Electronic address: Thiel@bio.tu-darmstadt.de.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Thiel
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000378:metabolism; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D017862:Phycodnaviridae / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D015221:Potassium Channels; D014764:Viral Proteins
keywords: Dual sorting; Mitochondria/plasma membrane sorting; Transmembrane domain; Viral K(+) channels