The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of. beta. -glucuronidase

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.87.20.8036· OSTI ID:5584119

Watanabe, H; Grubb, J H; Sly, W S ^[1]

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1. Saint Louis Univ. School of Medicine, MO (USA)

The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human {beta}-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3{percent} of the total functional receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of {beta}-glucuronidase. At pH 7.5, the rate of endocytosis was only 14{percent} the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized {beta}-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized {beta}-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor.

• OSTI ID: 5584119
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 87:20; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOHYDRATES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CYSTEINE
DAYS LIVING RADIOISOTOPES
DNA
ELECTROPHORESIS
ENZYMES
EVEN-ODD NUCLEI
GENE REGULATION
GLUCURONIDASE
GLYCOSYL HYDROLASES
HEXOSES
HYDROLASES
ISOTOPES
L CELLS
LIGHT NUCLEI
LYSOSOMES
LYSOZYME
MAMMALS
MAN
MANNOSE
MEMBRANE PROTEINS
MICE
MONOSACCHARIDES
NUCLEI
NUCLEIC ACIDS
O-GLYCOSYL HYDROLASES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOIDS
PERMEABILITY
PRIMATES
PROTEINS
RADIOISOTOPES
RECEPTORS
RECOMBINANT DNA
RODENTS
SACCHARIDES
SECRETION
SULFUR 35
SULFUR ISOTOPES
THIOLS
VERTEBRATES