It has been proposed that the nuclear rather than a mitochondrial or cytoplasmic localization for FKBP51 strongly depends on the involvement of its TPR domain since TPR mutants unable to interact with Hsp90 show a constitutively nuclear FKBP51 [17], and it is the case for a spliced variant lacking the TPR domain that has been found in melanoma patients [52]. This evidence concerns the gene FKBP4 and melanoma.