FKBP4
Domain
The PPIase activity is mainly due to the first PPIase FKBP-type domain (1-138 AA).
The C-terminal region (AA 375-458) is required to prevent tubulin polymerization.
The chaperone activity resides in the C-terminal region, mainly between amino acids 264 and 400.
The TPR repeats mediate mitochondrial localization.
Function
Immunophilin protein with PPIase and co-chaperone activities. Component of steroid receptors heterocomplexes through interaction with heat-shock protein 90 (HSP90). May play a role in the intracellular trafficking of heterooligomeric forms of steroid hormone receptors between cytoplasm and nuclear compartments. The isomerase activity controls neuronal growth cones via regulation of TRPC1 channel opening. Acts also as a regulator of microtubule dynamics by inhibiting MAPT/TAU ability to promote microtubule assembly. May have a protective role against oxidative stress in mitochondria.
Post-translational modifications
Phosphorylation by CK2 results in loss of HSP90 binding activity.
Tissue Specificity
Widely expressed.
Cellular localization
- Cytoplasm
- Cytosol
- Mitochondrion
- Nucleus
- Cytoplasm
- Cytoskeleton
- Cell projection
- Axon
- Shuttles from mitochondria to nucleus; co-localizes in mitochondria with the glucocorticoid receptor (PubMed:21730050). Colocalized with MAPT/TAU in the distal part of the primary cortical neurons (By similarity).
Alternative names
FKBP52, FKBP4, Peptidyl-prolyl cis-trans isomerase FKBP4, PPIase FKBP4, 51 kDa FK506-binding protein, 52 kDa FK506-binding protein, 59 kDa immunophilin, FK506-binding protein 4, FKBP59, HSP-binding immunophilin, Immunophilin FKBP52, Rotamase, FKBP51, 52 kDa FKBP, FKBP-52, p59, FKBP-4, HBI