FKHR (for forkhead in rhabdomyosarcoma) and FKHRL1 are members of the
forkhead family of transcription factors. Transcriptional activation of FKHR
proteins is regulated by the serine/threonine kinase Akt1, which phosphorylates
FKHRL1 and results in FKHRL1 associating with 14-3-3 proteins and
being retained in the cytoplasm. Induction of apoptosis or withdrawal of
growth factors stimulates dephosphorylation and nuclear translocation
of FKHR proteins, leading to FKHR-induced gene-specific transcriptional
activation. FKHR, also designated forkhead box protein O1A (FOXO1), is
an ubiquitously expressed protein that shuttles between the cytoplasm and
nucleus. Genetic mutations in FKHR genes, including the t(2;13) and t(1;3)
translocations, are commonly found in alveolar rhabdomyosarcomas.