Central role of the oxygen-dependent degradation domain of Drosophila HIFalpha/Sima in oxygen-dependent nuclear export.
The Drosophila HIFalpha homologue, Sima, is localized mainly in the cytoplasm in normoxia and accumulates in the nucleus upon hypoxic exposure. We have characterized the mechanism governing Sima oxygen-dependent subcellular localization and found that Sima shuttles continuously between the nucleus and the cytoplasm. We have previously shown that nuclear import depends on an atypical bipartite nuclear localization signal mapping next to the C-terminus of the protein. We show here that nuclear export is mediated in part by a CRM1-dependent nuclear export signal localized in the oxygen-dependent degradation domain (ODDD). CRM1-dependent nuclear export requires both oxygen-dependent hydroxylation of a specific prolyl residue (Pro850) in the ODDD, and the activity of the von Hippel Lindau tumor suppressor factor. At high oxygen tension rapid nuclear export of Sima occurs, whereas in hypoxia, Sima nuclear export is largely inhibited. HIFalpha/Sima nucleo-cytoplasmic localization is the result of a dynamic equilibrium between nuclear import and nuclear export, and nuclear export is modulated by oxygen tension.
Irisarri
Maximiliano
M
Instituto Leloir and FCEyN, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, 1405 Buenos Aires, Argentina.
Lavista-Llanos
Sofía
S
Romero
Nuria M
NM
Centanin
Lázaro
L
Dekanty
Andrés
A
Wappner
Pablo
P
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D049790:Nuclear Export Signals; D010100:Oxygen / Q000378:metabolism*; D011393:Procollagen-Proline Dioxygenase / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D019076:Transgenes; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D049790:Nuclear Export Signals; D011993:Recombinant Fusion Proteins; C100429:Sima protein, Drosophila; D011393:Procollagen-Proline Dioxygenase; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D010100:Oxygen