FKBPs: at the crossroads of folding and transduction

FK506-binding proteins (FKBPs) belong to the large family of peptidyl-proly l cis-trans isomerases, which are known to be involved in many cellular pro cesses, such as cell signalling, protein trafficking and transcription. FKB Ps associate into protein complexes, although the involvement and precise r ole of their foldase activity remain to be elucidated. FKBPs represent a la rge gene family in plants that is involved in growth and development. Disru ption of genes encoding FKBPs in plants and animals has underlined the impo rtance of this family of proteins in the regulation of cell division and di fferentiation.