cartilage intermediate layer protein 1 (CILP-1, CILP)

Function: 1) cartilage scaffolding 2) antagonizes TGFB1 & IGF1 (putative) 3) suppresses IGF1-induced proliferation & sulfated proteoglycan synthesis 4) inhibits ligand-induced IGF1R autophosphorylation 5) interacts with TGFB1 - inhibits TGFB1-mediated induction of cartilage matrix genes (putative) 6) cleaved into 2 chains by a furin-like protease upon or preceding secretion (putative) Structure: - contains 1 Ig-like C2-type domain (immunoglobulin-like domain) - contains 1 TSP type-1 domain Compartment: secreted, extracellular matrix Expression: - specifically expressed in cartilage - localizes in the intermediate layer of articular cartilage but neither in the superficial nor in the deepest regions - specifically expressed in intervertebral disk tissue - expression increases with aging in hip articular cartilage. Pathology: 1) overexpression may lead to impair chondrocyte growth & matrix repair & indirectly promote inorganic pyrophosphate supersaturation in aging & osteoarthritis cartilage 2) overexpressed in articular hyaline cartilage from patients with calcium pyrophosphate dihydrate crystal deposition disease (CPPD) 3) defects in CILP may be a cause of susceptibility to lumbar disk disease 4) antibodies against CILP are detected in patients with early-stage knee osteoarthritis (OA) & rheumatoid arthritis - autoantibodies against the C1 & C2 chains are detected in 10/136 (C1) & 17/136 (C2) patients with OA

General

glycoprotein secreted protein

Properties

SIZE: MW = 133 kD entity length = 1184 aa COMPARTMENT: extracellular compartment MOTIF: signal sequence {1-21} N-glycosylation site {N129} N-glycosylation site {N132} TSP TYPE-1 {149-201} MOTIF: cysteine residue {C161} MODIFICATION: cysteine residue {C195} cysteine residue {C165} MODIFICATION: cysteine residue {C200} cysteine residue {C177} MODIFICATION: cysteine residue {C185} cysteine residue {C185} MODIFICATION: cysteine residue {C177} cysteine residue {C195} MODIFICATION: cysteine residue {C161} cysteine residue {C200} MODIFICATION: cysteine residue {C165} immunoglobulin superfamily domain {309-395} MOTIF: cysteine residue {C330} MODIFICATION: cysteine residue {C376} N-glycosylation site {N346} cysteine residue {C376} MODIFICATION: cysteine residue {C330} N-glycosylation site {N420} N-glycosylation site {N550} N-glycosylation site {N631} N-glycosylation site {N1000} N-glycosylation site {N1056}

Database Correlations

OMIM 603489 MORBIDMAP 603489 UniProt O75339 PFAM correlations

References

UniProt :accession O75339