Recombinant Human HSP70/HSPA1A Protein, CF

Heat Shock 70kDa Protein (HSP70), also known as Heat Shock 70kDa Protein 1A (HSPA1A), is a 641 amino acid (aa) member of the HSP70 family of molecular chaperones with a predicted molecular weight of 70 kDa. Human HSP70/HSPA1A shares 95% and 97% aa sequence identity with the mouse and rat orthologs, respectively. It has an N-terminal nucleotide-binding domain, which contains ATPase activity, and a C-terminal substrate-binding domain (1). HSP70/HSPA1A promotes the proper folding of nascent polypeptides and assists in the refolding of denatured proteins (2). However, if either of these processes proceeds too slowly or fails, HSP70/HSPA1A can interact with the HSP40 co-chaperone protein and the CHIP/STUB1 Ubiquitin ligase (E3) to promote ubiquitination and degradation of the nascent polypeptide or denatured protein (3,4). HSP70/HSPA1A can be regulated post-translationally via multiple mechanisms, including phosphorylation, ubiquitination, and methylation (5-8). For example, unmethylated HSP70/HSPA1A localizes to the cytoplasm, but following methylation on Lys561 it is found only in the nucleus (8). Pathologically, HSP70/HSPA1A has been implicated in the promotion of multiple cancer types (8-10). Conversely, it is thought to protect against several neurodegenerative diseases that are caused by the accumulation of misfolded proteins (11,12).