Molecular chaperone; assists the folding of proteins upon ATP hydrolysis. Known to play a role, in vitro, in the folding of actin and tubulin. Heterooligomeric complex of about 850 to 900 kDa that forms two stacked rings, 12 to 16 nm in diameter (PubMed:11599560). Interacts with CCT8 (PubMed:21868675). Embryonic lethal. Belongs to the TCP-1 chaperonin family.