Endocytosis of a small dermatan sulphate proteoglycan. Identification of binding proteins.
Endosomal preparations from human osteosarcoma cells and from fibroblasts contain 51,000- and 26,000-Mr proteins which bind a small dermatan sulphate proteoglycan after SDS/polyacrylamide-gel electrophoresis and Western blotting. Binding can be inhibited by unlabelled proteoglycan core protein. The proteins co-precipitate with a proteoglycan core protein-antibody complex. Scatchard analysis of immobilized endosomal proteins yielded a KD of about 37 nM for the proteoglycan. In intact cells proteins of the same size can be found. They are sensitive to trypsinization. A 51,000-Mr protein is the predominant membrane protein with strong binding to immobilized dermatan sulphate proteoglycan. There are additional proteoglycan-binding proteins with Mr values of around 30,000 and 14,000 which are insensitive to trypsin treatment. In contrast with the 51,000- and 26,000-Mr proteins, they resist deoxycholate/Triton X-100 extraction several days after subcultivation.
Hausser
H
H
Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Federal Republic of Germany.
Hoppe
W
W
Rauch
U
U
Kresse
H
H
D053674:Aggrecans; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D004705:Endocytosis; D016326:Extracellular Matrix Proteins; D005347:Fibroblasts / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D037181:Lectins, C-Type; D009363:Neoplasm Proteins / Q000378:metabolism*; D012516:Osteosarcoma / Q000378:metabolism; D011233:Precipitin Tests; D011509:Proteoglycans; D014407:Tumor Cells, Cultured
D053674:Aggrecans; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D037181:Lectins, C-Type; D009363:Neoplasm Proteins; D011509:Proteoglycans