HIF-alpha is translocated into the nucleus (Kallio et al. 1998, Depping et al. 2008, Chachami et al. 2009). Importin 4 and importin 7 (Chachami et al. 2009) as well as the importin alpha/beta pathway (Depping et al. 2008) appear to be capable of interacting with HIF-alpha. During hypoxia HIF-alpha accumulates in the nucleus where it associates with CBP and p300 (Kallio et al. 1998).