The low density lipoprotein receptor-related protein/alpha2-macroglobulin receptor is a receptor for connective tissue growth factor.
Connective tissue growth factor (CTGF) expression is regulated by transforming growth factor-beta (TGF-beta) and strong up-regulation occurs during wound healing; in situ hybridization data indicate that there are high levels of CTGF expression in fibrotic lesions. Recently the binding parameters of CTGF to both high and lower affinity cell surface binding components have been characterized. Affinity cross-linking and SDS-polyacrylamide gel electrophoresis analysis demonstrated the binding of CTGF to a cell surface protein with a mass of approximately 620 kDa. We report here the purification of this protein by affinity chromatography on CTGF coupled to Sepharose and sequence information obtained by mass spectroscopy. The binding protein was identified as the multiligand receptor, low density lipoprotein receptor-related protein/alpha2-macroglobulin receptor (LRP). The identification of LRP as a receptor for CTGF was validated by several studies: 1) binding competition with many ligands that bind to LRP, including receptor-associated protein; 2) immunoprecipitation of CTGF-receptor complex with LRP antibodies; and 3) cells that are genetically deficient for LRP were unable to bind CTGF. Last, CTGF is rapidly internalized and degraded and this process is LRP-dependent. In summary, our data indicate that LRP is a receptor for CTGF, and may play an important role in mediating CTGF biology.
Segarini
P R
PR
FibroGen, Inc., South San Francisco, California 94080, USA.
Nesbitt
J E
JE
Li
D
D
Hays
L G
LG
Yates
J R
JR
Carmichael
D F
DF
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002846:Chromatography, Affinity; D055513:Connective Tissue Growth Factor; D004591:Electrophoresis, Polyacrylamide Gel; D006133:Growth Substances / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D017874:Immediate-Early Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D026563:LDL-Receptor Related Protein-Associated Protein / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011485:Protein Binding
C526318:CCN2 protein, mouse; D006133:Growth Substances; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D026563:LDL-Receptor Related Protein-Associated Protein; D055513:Connective Tissue Growth Factor