title: Rapid recycling of ClC-2 chloride channels between plasma membrane and endosomes: role of a tyrosine endocytosis motif in surface retrieval.
abstract: ClC-2 chloride channel is present in the brain and some transporting epithelia where its function is poorly understood. We have now demonstrated that the surface channels are rapidly internalised and approximately the 70% of the surface membrane protein recycles after 4- to 8-min internalisation. Endocytosis of ClC-2 was dependent upon tyrosine 179 located within an endocytic motif. Rapid recycling accompanied by an even faster internalisation could account for the abundant presence of ClC-2 in intracellular membranous structures. At least a proportion of ClC-2 resides in lipid rafts. Use of beta-cyclodextrin led to an increase in cell surface channel, but, surprisingly, a decrease in functionally active channels. We suggest that ClC-2 requires residing in beta-cyclodextrin sensitive clusters with other molecules in order to remain active. Regulation of ClC-2 trafficking to and within the membrane could be a means of modulating its activity.
authors.affiliation: Centro de Estudios Científicos (CECS), Valdivia, Chile.
authors.forename: Isabel
authors.initials: I
authors.lastname: Cornejo
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Niemeyer
authors.forename: Leandro
authors.initials: L
authors.lastname: Zúñiga
authors.forename: Yamil R
authors.initials: YR
authors.lastname: Yusef
authors.forename: Francisco V
authors.initials: FV
authors.lastname: Sepúlveda
authors.forename: L Pablo
authors.initials: LP
authors.lastname: Cid
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D019943:Amino Acid Substitution / Q000502:physiology; D000643:Ammonium Chloride / Q000494:pharmacology; D000730:Androstadienes / Q000494:pharmacology; D000090007:CLC-2 Chloride Channels; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D018118:Chloride Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006388:Hemagglutinins / Q000235:genetics; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D021962:Membrane Microdomains / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D014162:Transfection; D014443:Tyrosine / Q000235:genetics*; D000077191:Wortmannin; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D000730:Androstadienes; D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D004791:Enzyme Inhibitors; D006388:Hemagglutinins; D011993:Recombinant Fusion Proteins; D047392:beta-Cyclodextrins; D000643:Ammonium Chloride; D014443:Tyrosine; D000077191:Wortmannin