FK506-binding protein 8 (38 kD FK506-binding protein homolog, FKBP8, FKBP38, FKBPR38)

Function

• constitutively inactive PPiase, which becomes active when bound to calmodulin & Ca+2
• seems to act as a chaperone for BCL2, targets it to mitochondria & modulates its phosphorylation state
• BCL2/FKBP8/calmodulin/Ca+2 complex probably interferes with binding of BCL2 to its targets; active form of FKBP8 may thus play a role in the regulation of apoptosis
• forms heterodimer with calmodulin
• when activated by calmodulin & Ca+2, interacts with the BH4 domain of BCL2 & weakly with BCLX isoform Bcl-X(L)
• does not bind & inhibit calcineurin
• interacts with HCV NS5A
• binds the immunosuppressant FK506 only in its calmodulin/Ca+2 activated form

peptidylproline (omega=180) <--> peptidylproline (omega=0)

Cofactor: Ca+2

Structure

• homomultimers or heteromultimers (putative)
• contains 1 PPIase FKBP-type domain
• contains 3 TPR repeats

Compartment

mitochondrial membrane

Expression

• widely expressed
• highest levels seen in the brain

More general terms

• FK506 binding protein (FKBP)

Database

• UniProt: http://www.uniprot.org/uniprot/Q14318.html
• OMIM: https://mirror.omim.org/entry/604840