HSPA9 is encoded by the HSPA9 gene, which is located on chromosome 5, band q31.1 . This region is frequently deleted in myeloid leukemias and myelodysplasia (MDS), suggesting that HSPA9 may function as a tumor suppressor gene . The protein itself has a molecular weight of approximately 71 kDa and consists of 654 amino acids .
HSPA9 functions primarily as a molecular chaperone. It assists in the proper folding of newly synthesized polypeptides, refolding of denatured proteins, and stabilization of native proteins . Additionally, HSPA9 is involved in the inhibition of nuclear translocation, transcriptional activation, and control of centrosome-duplication functions of the p53 protein .
Due to its role in protein folding and stress response, HSPA9 is implicated in various diseases, including cancer and autoimmune disorders . Its overexpression has been observed in inflamed tissues, and it has been shown to have immunosuppressive activity by downregulating nuclear factor-kappa B (NF-κB) activation . This makes HSPA9 a potential target for therapeutic interventions in conditions such as rheumatoid arthritis and other autoimmune diseases .
Recombinant HSPA9 is produced using Escherichia coli (E. coli) expression systems and is purified using conventional chromatography techniques . The recombinant protein is often tagged with a His-tag at the N-terminus to facilitate purification and detection . It is typically formulated in a buffer containing Tris-HCl, DTT, and glycerol to maintain stability and activity .