title: Molecular characterization of arylsulfatase G: expression, processing, glycosylation, transport, and activity.
abstract: Arylsulfatase G (ARSG) is a recently identified lysosomal sulfatase that was shown to be responsible for the degradation of 3-O-sulfated N-sulfoglucosamine residues of heparan sulfate glycosaminoglycans. Deficiency of ARSG leads to a new type of mucopolysaccharidosis, as described in a mouse model. Here, we provide a detailed molecular characterization of the endogenous murine enzyme. ARSG is expressed and proteolytically processed in a tissue-specific manner. The 63-kDa single-chain precursor protein localizes to pre-lysosomal compartments and tightly associates with organelle membranes, most likely the endoplasmic reticulum. In contrast, proteolytically processed ARSG fragments of 34-, 18-, and 10-kDa were found in lysosomal fractions and lost their membrane association. The processing sites and a disulfide bridge between the 18- and 10-kDa chains could be roughly mapped. Proteases participating in the processing were identified as cathepsins B and L. Proteolytic processing is dispensable for hydrolytic sulfatase activity in vitro. Lysosomal transport of ARSG in the liver is independent of mannose 6-phosphate, sortilin, and Limp2. However, mutation of glycosylation site N-497 abrogates transport of ARSG to lysosomes in human fibrosarcoma cells, due to impaired mannose 6-phosphate modification.
authors.affiliation: From the Department of Chemistry, Biochemistry I, Bielefeld University, 33615 Bielefeld.
authors.forename: Björn
authors.initials: B
authors.lastname: Kowalewski
authors.affiliation: From the Department of Chemistry, Biochemistry I, Bielefeld University, 33615 Bielefeld.
authors.forename: Torben
authors.initials: T
authors.lastname: Lübke
authors.affiliation: the Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg 20246, and.
authors.forename: Katrin
authors.initials: K
authors.lastname: Kollmann
authors.affiliation: the Department of Biochemistry, Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg 20246, and.
authors.forename: Thomas
authors.initials: T
authors.lastname: Braulke
authors.affiliation: the Institute of Molecular Medicine and Cell Research and BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg 79104, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinheckel
authors.affiliation: From the Department of Chemistry, Biochemistry I, Bielefeld University, 33615 Bielefeld, thomas.dierks@uni-bielefeld.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dierks
authors.affiliation: From the Department of Chemistry, Biochemistry I, Bielefeld University, 33615 Bielefeld, mdamme@biochem.uni-kiel.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Damme
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D001192:Arylsulfatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D008247:Lysosomes / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D010447:Peptide Hydrolases / Q000378:metabolism; D011498:Protein Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021381:Protein Transport
chemical_list: D011498:Protein Precursors; C476553:ARSG protein, human; C000593694:arylsulfatase G, mouse; D001192:Arylsulfatases; D010447:Peptide Hydrolases
keywords: Arylsulfatase G; Enzyme Processing; Heparan Sulfate; Lysosomal Glycoprotein; Lysosomal Storage Disease; Lysosome; Mannose 6-Phosphate; Mucopolysaccharidosis; Proteolytic Processing; Sulfatase