title: Mucolipin controls lysosome exocytosis in Dictyostelium.
abstract: Mucolipidosis type IV is a poorly understood lysosomal storage disease caused by alterations in the mucolipin lysosomal Ca(2+) channel. In this study, we generated mucolipin-knockout Dictyostelium cells, and observed that lysosome exocytosis was markedly increased in these cells compared with wild-type cells. In addition, mucolipin-knockout cells were more resistant to Ca(2+) deprivation, and the Ca(2+) concentration in their secretory lysosomes was decreased, suggesting that mucolipin transfers Ca(2+) ions from the cytosol to the lumen of secretory lysosomes. We speculate that mucolipin attenuates the fusogenic effect of local cytosolic increases in Ca(2+) by dissipating them into the lumen of lysosomal compartments.
authors.affiliation: Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland. Wanessa.DeLima@unige.ch
authors.forename: Wanessa C
authors.initials: WC
authors.lastname: Lima
authors.forename: Florence
authors.initials: F
authors.lastname: Leuba
authors.forename: Thierry
authors.initials: T
authors.lastname: Soldati
authors.forename: Pierre
authors.initials: P
authors.lastname: Cosson
mesh_terms: D000595:Amino Acid Sequence; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004023:Dictyostelium / Q000235:genetics / Q000378:metabolism*; D005089:Exocytosis / Q000502:physiology; D055786:Gene Knockout Techniques; D006801:Humans; D008247:Lysosomes / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D009081:Mucolipidoses / Q000378:metabolism; D030781:Organisms, Genetically Modified; D010802:Phylogeny; D050051:Transient Receptor Potential Channels / Q000172:deficiency* / Q000235:genetics
chemical_list: D050051:Transient Receptor Potential Channels; D002118:Calcium