Organization and function of the FKBP52 and FKBP51 genes

Best established as components of steroid hormone receptor complexes, it is now clear that the large molecular weight immunophilins, FKBP52 and FKBP51, play important regulatory roles elsewhere in the cell. This review outlines what is known about the organization of the genes, FKBP4 and FKBP5, respectively, encoding these proteins and describes their diverse actions in the nervous system, reproduction, and cancer. The organization of FKBP4 and FKBP5 is very similar among the chordates, and gene expression is influenced by both genetic and epigenetic mechanisms. Recent studies identifying roles of FKBP52 and FKBP51 in the regulation of the microtubule-associated protein tau and microtubule assembly are discussed, as is their interaction with and influence on the transient receptor potential canonical (TRPC) subfamily of ion channel proteins.

► FKBP4 and FKBP5 have similar genomic organization, but differ in size.
► FKBP52 and FKBP51 exhibit similar domain structure.
► Recent studies on the functions of FKBP52 and FKBP51 are summarized.
► FKBP52 and FKBP51 affect microtubule assembly through association with tau protein.
► FKBP52 (and possibly FKBP51) interacts with transient receptor potential channels.