Increased striatal mRNA and protein levels of the immunophilin FKBP-12 in experimental Parkinson's disease and identification of FKBP-12-binding proteins.

FKBP-12, a 12 kDa FK506-binding protein (neuroimmunophilin), acts as a receptor for the immunosuppressant drug FK506. Neuroimmunophilins, including FKBP-12, are abundant in the brain and have been shown to be involved in reversing neuronal degeneration and preventing cell death. In this report, we have utilized several analytical techniques, such as in situ hybridization, Western blotting, two-dimensional gel electrophoresis, and liquid chromatography electrospray tandem mass spectrometry to study the transcriptional expression as well as protein levels of FKBP-12 in the unilateral 6-hydroxydopamine (6-OHDA) rat model of Parkinson's disease. The FKBP-12 protein was also detected directly on brain tissue sections using mass spectrometry profiling. We found increased levels of FKBP-12 mRNA and protein in the dorsal and middle part of the 6-OHDA lesioned striatum. Thus, these studies clearly demonstrate that FKBP-12 is increased in the brain of a common animal model of Parkinson's disease (PD). Additionally, we have identified potential binding partners to FKBP-12 that may be implicated in the pathophysiology of Parkinson's disease, such as alpha-enolase, 14-3-3 zeta/delta, pyruvate kinase isozymes, and heat shock protein 70, using surface plasmon resonance sensor technology in combination with mass spectrometry. In conclusion, these data strongly suggests that FKBP-12 is altered in an experimental model of PD.