Endo180 binds to the C-terminal region of type I collagen.
Type I collagen is a fibril-forming heterotrimer composed of two alpha1 and one alpha2 chains and plays a crucial role in cell-matrix adhesion and cell differentiation. Through a comprehensive differential display screening of oncogenic ras target genes, we have shown that the alpha1 chain of type I collagen (col1a1) is markedly down-regulated by the ras oncogene through the mitogen-activated protein kinase pathway. Although ras-transformed cells are no longer able to produce and secrete endogenous collagen, they can still adhere to exogenous collagen, suggesting that the cells express a collagen binding factor(s) on the cell surface. When the region of col1a1 encompassing the C-terminal glycine repeat and C-prodomain (amino acids 1000-1453) was affinity-labeled with human placental alkaline phosphatase, the secreted trimeric fusion protein could bind to the surface of Ras-transformed cells. Using biochemical purification followed by matrix-assisted laser desorption/ionization mass spectrometry analysis, we identified this collagen binding factor as Endo180 (uPARAP, CD280), a member of the mannose receptor family. Ectopic expression of Endo180 in CosE5 cells followed by in situ staining and quantitative binding assays confirmed that Endo180 indeed recognizes and binds to placental alkaline phosphatase. The interaction between Endo180 and the C-terminal region of type I collagen appears to play an important role in cell-matrix adhesion.
Thomas
Emily K
EK
Vanderbilt-Ingram Cancer Center, Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
Nakamura
Misa
M
Wienke
Dirk
D
Isacke
Clare M
CM
Pozzi
Ambra
A
Liang
Peng
P
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D019556:COS Cells; D002448:Cell Adhesion; D002454:Cell Differentiation; D002460:Cell Line; D002469:Cell Separation; D003094:Collagen / Q000378:metabolism / Q000494:pharmacology; D024042:Collagen Type I / Q000737:chemistry* / Q000378:metabolism; D000090602:Collagen Type I, alpha 1 Chain; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D004338:Drug Combinations; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D005353:Fibronectins / Q000737:chemistry; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005998:Glycine / Q000737:chemistry; D006801:Humans; D007797:Laminin / Q000494:pharmacology; D020935:MAP Kinase Signaling System; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010641:Phenotype; D010920:Placenta / Q000201:enzymology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D011975:Receptors, Mitogen / Q000737:chemistry* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors; D014162:Transfection; D018631:ras Proteins / Q000378:metabolism
D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D018076:DNA, Complementary; D004338:Drug Combinations; C408294:Endo180; D004791:Enzyme Inhibitors; D005353:Fibronectins; D007797:Laminin; D010455:Peptides; D011509:Proteoglycans; D034741:RNA, Small Interfering; D011975:Receptors, Mitogen; D011993:Recombinant Fusion Proteins; C059485:matrigel; D003094:Collagen; D000469:Alkaline Phosphatase; D018631:ras Proteins; D005998:Glycine