Disease relevance of NUTF2

• This level of catalytic activity represents minimally a 150-fold improvement in activity over the background rate for substrate dehydration and a dramatic step forward from the catalytically inert parent NTF2 [1].
• We analyzed dynamic properties of importin alpha, importin beta, Ran and NTF2 in nucleus, cytoplasm and at the nuclear pore of neuroblastoma cells using fluorescence correlation spectroscopy [2].

High impact information on NUTF2

• Structural basis for the recognition of a nucleoporin FG repeat by the NTF2-like domain of the TAP/p15 mRNA nuclear export factor [3].
• Binding sites of NTF2, the transport receptor of RanGDP, were observed in cytoplasmic filaments and central framework, but not nucleoplasmic filaments of the NPC [4].
• A direct NTF2-RanGDP interaction is crucial for this process, since point mutations that disturb the RanGDP-NTF2 interaction also interfere with Ran import [5].
• Previous studies have shown that immobilized recombinant p62 can bind the cytosolic nuclear import factor NTF2 and thereby deplete transport activity from cytosol [6].
• Structural similarities between the enzyme scytalone dehydratase with nuclear transport factor 2 (NTF2) suggested the potential for NTF2 to be re-engineered into a scytalone dehydratase-like enzyme [1].

Biological context of NUTF2

• Nucleotide-specific interaction of Ran/TC4 with nuclear transport factors NTF2 and p97 [7].
• Using structural, computational and biochemical analysis we have identified a functional site that is present throughout this superfamily, and our results indicate that this site functions as an NPC binding site in NTF2 [8].
• Peptide sequence analysis indicated that the purified protein was highly homologous to a previously identified human protein of unknown function called placental protein 15 (pp15) and to the predicted protein product of a yeast open reading frame from Saccharomyces cerevisiae [9].
• CONCLUSIONS: NTF2 represents a novel cross-reactive fungal allergen as demonstrated by sequence homology, three-dimensional modelling, inhibition experiments and skin test reactivity [10].

Anatomical context of NUTF2

• NTF2 has been shown to bind nuclear pore complex proteins and the GDP form of Ran in vitro [11].
• We also show that biotinylated NTF2-streptavidin microinjected into the cytoplasm accumulated at the nuclear envelope, indicating that NTF2 can target a binding partner to the nuclear pore complex [11].
• The results indicate that freely diffusing importin alpha, importin beta, Ran and NTF2 are in dynamic equilibrium with larger pools associated with immobile binding partners such as microtubules in the cytoplasm [2].
• Moreover, when injected into the cell nucleus, p10/NTF2 inhibited the nuclear export of NES-containing substrates [12].

Associations of NUTF2 with chemical compounds

• By preloading recombinant Ran/TC4 with [gamma-32P]GTP or [3H]GDP, we show that the interactions with p97 and NTF2 are specific for the GTP- and GDP-bound forms, respectively [7].
• We describe the identification and characterization of the RanGTPase and its binding partners: the guanine nucleotide exchange factor, RanGEF; the GTPase activating protein, RanGAP; the soluble import and export receptors; Ran-binding domain-(RBD) containing proteins; and NTF2 and related factors [13].
• A C-terminal helix found in scytalone dehydratase but absent in NTF2 also was added [1].
• Nuclear transport factor 2 represents a novel cross-reactive fungal allergen [10].

Regulatory relationships of NUTF2

• Monoclonal antibodies to NTF2 inhibit nuclear protein import by preventing nuclear translocation of the GTPase Ran [11].

Other interactions of NUTF2

• Surprisingly, we found that neither Xenopus ovarian cytosol nor a mixture of recombinant import factors (karyopherin alpha2, karyopherin beta1, Ran, and p10/NTF2) were able to support the import of pA-RCC1 into the nuclei of digitonin-permeabilized cells [14].
• A dominant-negative importin-beta mutant inhibited nuclear import of Ran, whereas addition of transportin, which accumulates in the nucleus, enhanced NTF2-dependent Ran import [15].

References