Members of this family, all eukaryotic, are part of the group II chaperonin complex called CCT (chaperonin containing TCP-1) or TRiC. The archaeal equivalent group II chaperonin is often called the thermosome. Both are somewhat related to the group I chaperonin of bacterial, GroEL/GroES. This family consists exclusively of the CCT zeta chain (part of a paralogous family) from animals, plants, fungi, and other eukaryotes.
Jiyao W et al.(2023). "The conserved domain database in 2023.",