title: Trafficking and assembly of the cold-sensitive TRPM8 channel.
abstract: TRPM (transient receptor potential melastatin-like) channels are distinct from many other members of the transient receptor potential family in regard to their overall size (>1000 amino acids), the lack of N-terminal ankyrin-like repeats, and hydrophobicity predictions that may allow for more than six transmembrane regions. Common to each TRPM member is a prominent C-terminal coiled coil region. Here we have shown that TRPM8 channels assemble as multimers using the putative coiled coil region within the intracellular C terminus and that this assembly can be disturbed by a single point mutation within the coiled coil region. This mutant neither gives rise to functional channels nor do its subunits interact or form protein complexes that correspond to a multimer. However, they are still transported to the plasma membrane. Furthermore, wild-type currents can be suppressed by expressing the membrane-attached C-terminal region of TRPM8. To separate assembly from trafficking, we investigated the maturation of TRPM8 protein by identifying and mutating the relevant N-linked glycosylation site and showing that glycosylation is neither essential for multimerization nor for transport to the plasma membrane per se but appears to facilitate efficient multimerization and transport.
authors.affiliation: Department of Pharmacology and Toxicology, University of Saarland, Medical Campus, 66421 Homburg, Germany.
authors.forename: Isabell
authors.initials: I
authors.lastname: Erler
authors.forename: Dalia M M
authors.initials: DM
authors.lastname: Al-Ansary
authors.forename: Ulrich
authors.initials: U
authors.lastname: Wissenbach
authors.forename: Thomas F J
authors.initials: TF
authors.lastname: Wagner
authors.forename: Veit
authors.initials: V
authors.lastname: Flockerzi
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Niemeyer
mesh_terms: D000818:Animals; D002460:Cell Line; D003080:Cold Temperature; D006801:Humans; D047468:Immunoprecipitation; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D021381:Protein Transport; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D011994:Recombinant Proteins; D050053:TRPM Cation Channels; C425966:TRPM8 protein, human