Active, Recombinant Human CHIP

Background: CHIP, encoded by the STUB1 gene, is a U-box–containing E3 ubiquitin ligase that also functions as a co-chaperone for heat shock proteins such as Hsp70 and Hsc70. It promotes ubiquitin-mediated degradation of misfolded or damaged proteins, linking chaperone activity to proteasomal protein quality control. CHIP binds chaperones through tetratricopeptide repeat domains and ubiquitinates their client substrates through its U-box domain. This activity regulates diverse cellular processes including stress responses, apoptosis, and protein homeostasis. CHIP also modulates immune signaling and degradation of regulatory proteins, and its dysfunction is linked to diseases such as spinocerebellar ataxia and cancer.