exportin-5 (Exp5, Ran-binding protein 21, XPO5, KIAA1291, RANBP21)

Function: 1) mediates the nuclear export of proteins bearing a double-stranded RNA binding domain & double-stranded RNAs (cargo) - XPO5 in the nucleus binds cooperatively to RNA & to the GTPase Ran in its active GTP-bound form (trimeric complex) - proteins containing double-stranded RNA binding domains can associate with this trimeric complex through RNA - docking of this complex to the nuclear pore complex is mediated through binding to nucleoporins - upon transit of a nuclear export complex into cytoplasm, hydrolysis of Ran-GTP to Ran-GDP (induced by RANBP1 & RANGAP1, respectively) cause disassembly of the complex & release of the cargo from the export receptor - XPO5 then returns to the nuclear compartment by diffusion through the nuclear pore complex, to mediate another round of transpor - directionality of nuclear export is thought to be conferred by an asymmetric distribution of the GTP- & GDP-bound forms of Ran between cytoplasm & nucleus 2) overexpression may in some circumstances enhance RNA-mediated gene silencing (RNAi). 3) mediates nuclear export of micro-RNA precursors, which form short hairpins - also mediates the nuclear export of synthetic short hairpin RNAs used for RNA interference - mediates nuclear export of deacylated & aminoacylated tRNAs - recognizes dsRNAs that lack a 5' overhang (sequence- independent), have only a short 3' overhang, & that have a double-stranded length of at least 15 base-pairs (Ran-GTP-dependent) 4) component of nuclear export receptor complexes - XPO5, Ran, dsRNA-binding proteins & dsRNA - XPO5, Ran, EEF1A1, & aminoacylated tRNA - XPO5, Ran, ILF3 & dsRNA - XPO5, Ran & pre-miRNA - XPO5, Ran, ILF3 & minihelix VA1 dsRNA - XPO5, RAN, ILF3, ZNF346 & dsRNA 5) interacts with EEF1A1, ILF3, NUP153, NUP214 & ZNF346 6) interacts with Ran & cargo proteins (GTP-dependent) Structure: - belongs to the exportin family Compartment: - nucleus, cytoplasm - shuttles between nucleus & the cytoplasm Alternative splicing: named isoforms=2 Expression: - expressed in heart, brain, placenta, lung, skeletal muscle, kidney, pancreas Pathology: - mediates the nuclear export of adenovirus VA1 dsRNA

Properties

SIZE: MW = 136 kD entity length = 1204 aa COMPARTMENT: cytoplasm cell nucleus MOTIF: Ran interaction {1-108} ILF3 interaction {533-640}

Database Correlations

OMIM 607845 UniProt Q9HAV4 Pfam PF08389

References

UniProt :accession Q9HAV4