Heparin binding protein-44 (HBP-44)/receptor-associated protein (RAP)mediates cell-substratum adhesion of mouse NIH/3T3 cells through its binding to low density lipoprotein (LDL) receptor-related protein (LRP).
The low density lipoprotein receptor-related protein (LRP) is a multifunctional endocytic receptor with the ability to bind and endocytose several structurally and functionally distinct ligands. The 39 kDa receptor-associated protein (RAP) is an endoplasmic reticulum (ER) resident protein, which is believed to function intracellularly as a molecular chaperone for LRP and to regulate its ligand binding activity along the secretory pathway. Mouse heparin binding protein-44 (HBP-44) is a homologue of human RAP. Using a recombinant form of HBP-44 expressed in Escherichia coli cells as a highly specific ligand for LRP, we demonstrated that HBP-44 coated on cell culture plates mediates the cell-substratum adhesion of mouse 3T3 fibroblasts in a dose-dependent manner, with 50% attachment at the concentration of 0.2 micrograms/ml. Ligand blot analysis with HBP-44 of whole cell extracts and the materials precipitated by anti-LRP antibodies revealed that the receptor for HBP-44 on NIH/3T3 cells was LRP. The results suggest that LRP serves as a cell adhesion receptor in some cells.
Terada
H
H
Department of Biochemistry Faculty of Medicine, Kagoshima University Japan.
Tsutsui
J
J
Sanada
J
J
Arima
T
T
Ozawa
M
M
D016475:3T3 Cells / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002448:Cell Adhesion; D006023:Glycoproteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D026563:LDL-Receptor Related Protein-Associated Protein; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D051379:Mice; D011971:Receptors, Immunologic / Q000276:immunology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
D002352:Carrier Proteins; D006023:Glycoproteins; D026563:LDL-Receptor Related Protein-Associated Protein; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D011971:Receptors, Immunologic; D011994:Recombinant Proteins