InterPro domain: IPR023566

FK506-binding proteins (FKBPs) are a particular class of peptidyl-prolyl cis-trans isomerases (PPIases) ( 5.2.1.8 ) [ 1 ]. This entry represents a group of nuclear FK506-binding proteins that act as histone chaperones. They each containing an extended acidic domain in addition to the conserved FK506-binding/peptidylprolyl isomerase (PPIase) domain. The PPIase domain has been shown to regulate histone H3 methylation, while the acidic domain has been shown to facilitate histone deposition and may regulate rDNA silencing [ 2 , 3 ].

This entry includes Fpr3 and its paralogue, Fpr4, from budding yeasts. They have been shown to affect genome-wide genes transcription [ 4 ].

This entry also includes AtFKBP53 from Arabidopsis and SpFkbp39p from Schizosaccharomyces pombe. AtFKBP53 possesses histone chaperone activity and is required for repressing ribosomal gene expression in Arabidopsis [ 4 ]. SpFkbp39p is a histone chaperone regulating rDNA silencing [ 5 ].

1. Insights into the catalytic mechanism of peptidyl prolyl cis/trans isomerases. Front. Biosci. 9, 3453-78
2. Nuclear FKBPs, Fpr3 and Fpr4 affect genome-wide genes transcription. Mol. Genet. Genomics 289, 125-36
3. A nuclear FK506-binding protein is a histone chaperone regulating rDNA silencing. Nat. Struct. Mol. Biol. 11, 275-83
4. AtFKBP53 is a histone chaperone required for repression of ribosomal RNA gene expression in Arabidopsis. Cell Res. 20, 357-66