title: Lcb4p sphingoid base kinase localizes to the Golgi and late endosomes.
abstract: Sphingoid long chain base phosphates (LCBPs) regulate cell proliferation, survival and motility in mammals. To learn more about LCBPs in Saccharomyces cerevisiae, we determined the cellular location of Lcb4p, the major enzyme catalyzing LCBP synthesis. By indirect immunofluorescence microscopy and subcellular fractionation, Lcb4p localizes to the trans-Golgi network and late endosomes and cycles between these compartments. Lcb4p faces the cytosol and is probably bound to membranes by protein-protein interactions. These results indicate that LCBs made in the endoplasmic reticulum must transit to the Golgi to be converted into LCBPs, which must then return to the endoplasmic reticulum to be degraded.
authors.affiliation: Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
authors.forename: Nitai C
authors.initials: NC
authors.lastname: Hait
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Fujita
authors.forename: Robert L
authors.initials: RL
authors.lastname: Lester
authors.forename: Robert C
authors.initials: RC
authors.lastname: Dickson
mesh_terms: D002462:Cell Membrane / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D011992:Endosomes / Q000201:enzymology*; D019084:Fluorescent Antibody Technique, Indirect; D006056:Golgi Apparatus / Q000201:enzymology*; D008856:Microscopy, Fluorescence; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; C113962:LCB4 protein, S cerevisiae; D017853:Phosphotransferases (Alcohol Group Acceptor)