CCT chaperonin regulates the folding of important proteins including actin, α-tubulin and β-tubulin. Reconstruction of CCT, which showed a substrate in the inner cavities of both rings α-tubulin and β-tubulin (both in blue surface and grey ribbons).

Protein folding is assisted by molecular chaperones. CCT (chaperonin containing TCP-1, or TRiC) is a 1-MDa oligomer that is built by two rings comprising eight different 60-kDa subunits. This chaperonin regulates the folding of important proteins including actin, α-tubulin and β-tubulin.