title: CRM1-mediated nuclear export determines the cytoplasmic localization of the antiapoptotic protein Survivin.
abstract: Survivin is a member of the inhibitor of apoptosis (IAP) family of negative regulators of programmed cell death that is frequently overexpressed in human tumors. Survivin is not only involved in the regulation of apoptosis, but is also known to play a role in the control of cell cycle progression at the G2/M phase. Survivin is a predominantly cytoplasmic protein expressed in a cell cycle-dependent manner, but the mechanism(s) that determine its nuclear-cytoplasmic localization have not been described. In this study, we report that Survivin is a nuclear shuttling protein that is actively exported from the nucleus via the CRM1-dependent pathway. Nuclear export of Survivin is independent of the export of other shuttling proteins that control the G2/M phase transition, such as cyclin B1 and cdc25. The carboxy-terminal domain of Survivin is both necessary and sufficient for its nuclear export, although this region does not contain a functional leucine-rich nuclear export signal. Differences in the amino acid sequence of this region determine the dramatically different localization of Survivin (in the cytoplasm) and its splicing variant Survivin-DeltaEx3 (in the nucleus). The carboxy-terminal end of Survivin-DeltaEx3 contains a bipartite nuclear localization signal, not present in Survivin, which mediates its strong nuclear accumulation. These data suggest that active transport between the nucleus and cytoplasm may constitute an important regulatory mechanism for Survivin function.
authors.affiliation: Department of Medical Oncology, VU University Medical Center, Amsterdam, HV1081, The Netherlands. ja.rodriguez@vumc.nl
authors.forename: Jose A
authors.initials: JA
authors.lastname: Rodríguez
authors.forename: Simone W
authors.initials: SW
authors.lastname: Span
authors.forename: Carlos G M
authors.initials: CG
authors.lastname: Ferreira
authors.forename: Frank A E
authors.initials: FA
authors.lastname: Kruyt
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giaccone
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001693:Biological Transport, Active; D002451:Cell Compartmentation; D018797:Cell Cycle Proteins / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D028884:Karyopherins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear; D000077022:Survivin; D000097606:Exportin 1 Protein
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D051034:Inhibitor of Apoptosis Proteins; D028884:Karyopherins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D018160:Receptors, Cytoplasmic and Nuclear; D000077022:Survivin; D000097606:Exportin 1 Protein; C107489:BIRC5 protein, human