Heat Shock Protein 47, Recombinant, Human (HSP47, Colligin, gp46, AsTP3, CBP1, CBP2, Collagen-bindin

Hsp47 is a novel 47kD stress glycoprotein. The expression of Hsp47 is highly tissue as well as cell-specific and restricted to mostly phenotypically altered collagen-producing cells (1)., Prior to secretion, procollagen molecules are correctly folded to triple helices in the ER where Hsp47 specifically associates with procollagen during its folding and/or modification, processes and is thought to function as a collagen-specific molecular chaperone (2). Although the structural requirements for structural recognition and regulation of the binding have not yet been elucidated, it has been proposed that Hsp47 dissociates from procollagen during the process of proly 4-hydroxylation in the ER (3). The expression of Hsp47 is always noted during the process of fibrosis especially around the fibrotic lesions in both humans and experimental animals. These observations suggest that upregulation of Hsp47 may play an important role in the subsequent fibrotic process, possibly by regulation increased synthesis/assembly of collagens (4). Analysis of the amino acid sequence reveals that Hsp47 is a unique member of the serpin superfamily but unlike other members of the sepin family, such as alpha1-antitrypsin, antithrombin and ovalbumin which are all exported from the ER, Hsp47 is retained in the ER by its COOH-terminus RDEL peptide sequence (5). Although Hsp47 is a resident of the ER, this chaperone is exported from the ER into pre-Golgi vesicles. Hsp47 remains associated with procollagen up to the cis-Golgi compartment where it dissociates from its substrate in a pH-independent but concentration dependent manner and is recycled back to the ER (6). No specific receptor has been delineated for the RDEL COOH-terminal retention sequence of Hsp47. However, recent studies have demonstrated that the Hsp47 is distributed, coprecipitates with and binds to the KDEL receptor (erd2 gene product). It has also been shown that under conditions of stress and alterations of intra-cellular pH (pHi), significant levels of hsp47 eludes erd2P retention and escape to the cell surface where it potentially may function as a serpin protein which may modulate cell migration during development and invasion and metastasis in cancer (7). Applications: Suitable for use in Western Blot. Recommended Dilution: Western Blot: We recommend that the material be diluted in an appropriate volume of an SDS containing sample buffer (e.g. Laemmli, U.K., (1970) Nature 227: 680-685) and heated at 100°C for 5 min. prior to use. On a 15-well minigel system, 10ng of protein per lane should be sufficient. Storage and Stability: Aliquot to avoid repeated freezing and thawing and freeze at-70°C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.