title: Transmembrane domain length of viral K+ channels is a signal for mitochondria targeting.
abstract: K(+) channels operate in the plasma membrane and in membranes of organelles including mitochondria. The mechanisms and topogenic information for their differential synthesis and targeting is unknown. This article describes 2 similar viral K(+) channels that are differentially sorted; one protein (Kesv) is imported by the Tom complex into the mitochondria, the other (Kcv) to the plasma membrane. By creating chimeras we discovered that mitochondrial sorting of Kesv depends on a hierarchical combination of N- and C-terminal signals. Crucial is the length of the second transmembrane domain; extending its C terminus by > or = 2 hydrophobic amino acids redirects Kesv from the mitochondrial to the plasma membrane. Activity of Kesv in the plasma membrane is detected electrically or by yeast rescue assays only after this shift in sorting. Hence only minor structural alterations in a transmembrane domain are sufficient to switch sorting of a K(+) channel between the plasma membrane and mitochondria.
authors: Institute of Botany, Technische Universität Darmstadt, D-64287 Darmstadt, Germany.
authors: Jörg
authors: J
authors: Balss
authors: Panagiotis
authors: P
authors: Papatheodorou
authors: Mario
authors: M
authors: Mehmel
authors: Dirk
authors: D
authors: Baumeister
authors: Brigitte
authors: B
authors: Hertel
authors: Nicolas
authors: N
authors: Delaroque
authors: Franck C
authors: FC
authors: Chatelain
authors: Daniel L
authors: DL
authors: Minor
authors: James L
authors: JL
authors: Van Etten
authors: Joachim
authors: J
authors: Rassow
authors: Anna
authors: A
authors: Moroni
authors: Gerhard
authors: G
authors: Thiel
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins; D008928:Mitochondria / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D017862:Phycodnaviridae / Q000737:chemistry; D015221:Potassium Channels / Q000737:chemistry / Q000378:metabolism*; D021382:Protein Sorting Signals; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D008565:Membrane Proteins; D015221:Potassium Channels; D021382:Protein Sorting Signals; D014764:Viral Proteins