Arabidopsis thaliana type I and II chaperonins

An examination of the Arabidopsis thaliana genome sequence led to the ident ification of 29 predicted genes with the potential to encode members of the chaperonin family of chaperones (CPN60 and CCT), their associated cochaper onins, and the cytoplasmic chaperonin cofactor prefoldin. These comprise th e first complete set of plant chaperonin protein sequences and indicate tha t the CPN family is more diverse than previously described. In addition to surprising sequence diversity within CPN subclasses, the genomic data also suggest the existence of previously undescribed family members, including a 10-kDa chloroplast cochaperonin. Consideration of the sequence data descri bed in this review prompts questions about the complexities of plant CPN sy stems and the evolutionary relationships and functions of the component pro teins, most of which have not been studied experimentally.