Molecular chaperone; assists the folding of proteins upon ATP hydrolysis. Known to play a role, in vitro, in the folding of actin and tubulin. In yeast may play a role in mitotic spindle formation. Heterooligomeric complex of about 850 to 900 kDa that forms two stacked rings, 12 to 16 nm in diameter (By similarity). Interacts with PLP2; this interaction leads to inhibition of CCT complex mediated actin folding (PubMed:17429077). Belongs to the TCP-1 chaperonin family.