HSP40 Antibody #4868

HSP40 and HSP40-like proteins represent a large family of chaperone proteins that are homologous to E. coli DnaJ protein (1). These proteins are classified into three subtypes based on their structures. The common feature of the family is a conserved J domain, which is usually located at the amino terminus of proteins and responsible for their association with HSP70 (1,2). Human HSP40, also known as Hdj1, belongs to subtype II that contain a unique Gly/Phe-rich region (2). HSP40 family proteins bind unfolded proteins, prevent their aggregation, and then deliver them to HSP70 (2,3). Another major function of HSP40 is to stimulate ATPase activity of HSP70, which causes conformational change of the unfolded proteins (4,5). The HSP40-HSP70-unfolded protein complex further binds to co-chaperones Hip, Hop and HSP90 or components of the protein degradation machinery such as CHIP and BAG-1, which either leads to protein folding or degradation, respectively (6).