STIP1 Human, His
Description
Product Specs
Product Science Overview
Stress-Induced Phosphoprotein 1 (STIP1), also known as Hsp70-Hsp90 Organizing Protein (HOP), is a co-chaperone protein encoded by the STIP1 gene in humans. This protein plays a crucial role in the cellular stress response by facilitating the interaction between the major heat shock proteins Hsp70 and Hsp90 .
The STIP1 gene is located on chromosome 11q13.1 and consists of 14 exons . The protein itself is characterized by the presence of nine tetratricopeptide repeat (TPR) motifs, which are clustered into domains of three TPRs each. These TPR motifs are essential for mediating protein-protein interactions, allowing STIP1 to bind both Hsp70 and Hsp90 .
STIP1 functions as an adaptor protein that coordinates the activities of Hsp70 and Hsp90 in protein folding and stabilization. It assists in the transfer of client proteins from Hsp70 to Hsp90 by binding to both chaperones simultaneously . This interaction is critical for the proper folding of newly synthesized proteins and the refolding of denatured proteins under stress conditions .
The recombinant form of STIP1, tagged with a His (histidine) tag, is commonly produced using bacterial expression systems. The His tag facilitates the purification of the recombinant protein through affinity chromatography. The preparation involves cloning the STIP1 gene into an expression vector, transforming the vector into a suitable bacterial host (such as E. coli), inducing protein expression, and purifying the protein using a nickel-affinity column .
STIP1 undergoes various post-translational modifications, including phosphorylation. For instance, JAK2-mediated phosphorylation of STIP1 at tyrosine residues 134 and 152 has been shown to enhance its stability and promote its nuclear-cytoplasmic shuttling . This phosphorylation also increases STIP1’s resistance to cisplatin-induced cell death, highlighting its role in cancer cell proliferation and survival .
