CBP2 (Heat shock protein 47 or HSP47) is a collagen-specific molecular chaperone that is required for molecular maturation of various types of collagens.
There is a close association between increased expression of HSP47 and excessive accumulation of collagens in scar tissues of various human and experimental fibrotic diseases.
The increased levels of HSP47 in fibrotic diseases assist in excessive assembly and intracellular processing of procollagen molecules and, thereby, contribute to the formation of fibrotic lesions.
Suppression of HSP47 expression can reduce accumulation of collagens to delay the progression of fibrotic diseases in experimental animal models.
Because HSP47 is a specific chaperone for collagen synthesis, it provides a selective target to manipulate collagen production.
Colligins
Collagen-binding proteins, or colligins, are glycoproteins that bind specifically to collagen type I, collagen type IV, and gelatin.
Colligins are characterized by an amino acid structure that includes an N-terminal hydrophobic signal sequence and 2 putative N-linked oligosaccharide attachment sites.
Colligins also have a C-terminal RDEL sequence that acts as an endoplasmic reticulum (ER) retention sequence. Other features permit the colligin-binding protein of ER to be classified as a serpin (serine-arginine protease inhibitor).
References
Taguchi T, Razzaque MS. The collagen-specific molecular chaperone HSP47: is there a role in fibrosis? Trends Mol Med. 2007 Feb;13(2):45-53. PMID: 17169614