Heat shock protein 47

Heat shock protein 47, also known as SERPINH1 is a serpin which serves as a human chaperone protein for collagen.

Function
This protein is a member of the serpin superfamily of serine proteinase inhibitors. Its expression is induced by heat shock. HSP47 is expressed in the endoplasmic reticulum. These cells synthesize and secrete type I and type II collagen. The protein localizes to the endoplasmic reticulum lumen and binds collagen; thus it is thought to be a molecular chaperone involved in the maturation of collagen molecules. HSP47 is essential for the correct folding of procollagen. Antibodies directed to this protein have been found in patients with rheumatoid arthritis.

Structure
HSP47 contains 3 beta sheets and 9 alpha helices. After binding with collagen no conformation change is observed.

Interactions
Heat shock protein 47 has been shown to interact with collagens I, II, III, IV and V. It is involved in the secretion of collagen as well as the processing, assembly, and folding of collagen proteins. Hsp 47 binds specifically to procollagen and collagen only. The protein recognizes the triple helix of procollagen, two HSP47 proteins will bind to the leading and trailing strands of procollagen.

Research on role in preventing deep vein thrombosis
Research published in 2023 indicates a potential role of HSP47 regarding deep vein thrombosis. This initial research will be followed by additional studies.

Role in Fibrosis
Fibrosis is the scarring of connective tissue, one attribute is the excess deposition of collagen in the extracellular matrix of tissue. Research has shown that HSPs have a role in fibrotic diseases. HSP47 has been shown to be pro-fibrosis in various fibrotic diseases. During the process of fibrosis, HSP47 is expressed and is involved in the production of collagen. HSP47 could be a potential therapeutic agent for fibrotic disease, a down-regulation of HSP47 leads to decreased fibrotic progression.