FEATURES

FAMILY

DESCRIPTION

Also known as HS104_YEAST, HSP104. Required, in concert with Hsp40 (YDJ1) and Hsp70 (SSA1) and small Hsps (HSP26), for the dissociation, resolubilization and refolding of aggregates of damaged proteins after heat or other environmental stresses. Extracts proteins from aggregates by unfolding and threading them in an ATP-dependent process through the axial channel of the protein hexamer, after which they can be refolded by components of the Hsp70/Hsp40 chaperone system. Substrate binding is ATP-dependent, and release of bound polypeptide is triggered by ATP hydrolysis. Also responsible for the maintenance of prions by dissociating prion fibrils into smaller oligomers, thereby producing transmissible seeds that can infect daughter cells during mitosis and meiosis. Loss of HSP104 can cure yeast cells of the prions [PSI+], [URE3] and [PIN+]. Excess HSP104 can also specifically cure cells of [PSI+]. Homohexamer, forming a ring with a central pore. The hexamer is stabilized by high protein concentrations and by ADP or ATP. Oligomerization influences ATP hydrolysis activity at NBD2. Interacts with YDJ1. Interacts (via C-terminal DDLD tetrapeptide) with CNS1, CPR7 and STI1 (via TPR repeats); under respiratory growth conditions.

EXTERNAL LINKS

HSP104

Heat shock protein 104

HSP104

Molecular Synopsis