title: Characterization of the mannose 6-phosphate-dependent pathway of lysosomal enzyme routing in an invertebrate.
abstract: The mannose 6-phosphate (Man6P)-dependent pathway for routing lysosomal enzymes was characterized in the hepatopancreas of the estuary crab Chasmagnatus granulata: (a) an acid alpha-L-fucosidase was purified to homogeneity from the above-mentioned organ and was shown to contain mannose-linked phosphate residues; (b) high-mannose-type oligosaccharides isolated from a protein fraction enriched in acid hydrolases were found to contain acid-labile N-acetylglucosamine (GlcNAc) residues; (c) a membrane-bound UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase was detected that phosphorylated the estuary-crab alpha-L-fucosidase and bovine uteroferrin but not bovine pancreas ribonuclease B; (d) a GlcNAc-1-phosphodiester alpha-N-acetylglucosaminidase that released GlcNAc units from GlcNAc alpha 1-P6Man alpha 1-methyl was detected in microsomal membranes of the hepatopancreas; (e) two detergent-solubilized microsomal proteins having molecular masses of 205 and 215 kDa that were retained by a Man6P-rich mannan-Sepharose column, from where they were eluted with Man6P but not with glucose 6-phosphate, were recognized by antisera raised against bovine large (215 kDa) and small (46 kDa) Man6P receptors. This is the first description of all the components of the Man6P-dependent mechanism for routing lysosomal enzymes in an invertebrate.
authors.affiliation: Instituto de Investigaciones Bioquímicas Fundación Campomar, Buenos Aires, Argentina.
authors.forename: V
authors.initials: V
authors.lastname: Alvarez
authors.forename: A J
authors.initials: AJ
authors.lastname: Parodi
authors.forename: R
authors.initials: R
authors.lastname: Couso
mesh_terms: D000117:Acetylglucosamine / Q000032:analysis; D000135:Acid Phosphatase; D000818:Animals; D003386:Brachyura / Q000201:enzymology*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002417:Cattle; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004064:Digestive System / Q000201:enzymology; D004187:Disaccharides / Q000737:chemistry / Q000378:metabolism; D007527:Isoenzymes; D008247:Lysosomes / Q000201:enzymology*; D008360:Mannosephosphates / Q000378:metabolism*; D008667:Metalloproteins / Q000378:metabolism; D008861:Microsomes / Q000201:enzymology; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010179:Pancreas / Q000201:enzymology; D010727:Phosphoric Diester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D013379:Substrate Specificity; D000071681:Tartrate-Resistant Acid Phosphatase; D017855:Transferases (Other Substituted Phosphate Groups) / Q000302:isolation & purification / Q000378:metabolism*; D005644:alpha-L-Fucosidase / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D004187:Disaccharides; D007527:Isoenzymes; D008360:Mannosephosphates; D008667:Metalloproteins; D009844:Oligosaccharides; C027693:mannose-6-phosphate; D017855:Transferases (Other Substituted Phosphate Groups); C030012:UDP-N-acetylglucosamine-lysosomal-enzyme-N-acetylglucosaminephosphotransferase; D012260:Ribonucleases; C029600:ribonuclease B; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D010727:Phosphoric Diester Hydrolases; C026645:N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase; D005644:alpha-L-Fucosidase; D000117:Acetylglucosamine