@article{88486,
  keywords = {Animals, Humans, Drosophila, RNA, Messenger, Cell Line, Protein Binding, Recombinant Fusion Proteins, Microscopy, Fluorescence, Receptors, Cytoplasmic and Nuclear, Dimerization, Genes, Reporter, Carrier Proteins, Nuclear Proteins, Cell Nucleus, Cytoplasm, Fluorescent Dyes, Active Transport, Cell Nucleus, Drosophila Proteins, RNA-Binding Proteins, Two-Hybrid System Techniques, Receptors, CCR5, Nucleocytoplasmic Transport Proteins, Karyopherins, Nuclear Pore, Nuclear Pore Complex Proteins},
  author = {Heather Wiegand and Glen Coburn and Yan Zeng and Yibin Kang and Hal Bogerd and Bryan Cullen},
  title = {Formation of Tap/NXT1 heterodimers activates Tap-dependent nuclear mRNA export by enhancing recruitment to nuclear pore complexes.},
  abstract = {<p>The Tap protein has been shown to activate the nuclear export of mRNA species bearing retroviral constitutive transport elements and is also believed to play an essential role in the sequence nonspecific export of cellular mRNAs. However, it has remained unclear how Tap activity is regulated in vivo. Here, we report that the small NXT1/p15-1 protein functions as a critical cofactor for Tap-mediated mRNA export in both human and invertebrate cells. In the absence of NXT1 binding, the Tap protein is unable to effectively interact with components of the nuclear pore complex and both Tap nucleocytoplasmic shuttling and the nuclear export of mRNA molecules tethered to Tap are therefore severely attenuated. Formation of a Tap/NXT1 heterodimer enhances nucleoporin binding both in vitro and in vivo and induces the formation of a Tap/NXT1/nucleoporin ternary complex that is likely to be a key intermediate in the process of nuclear mRNA export. The critical importance of NXT1 for the nuclear export of poly(A)(+) RNA is emphasized by the finding that specific inhibition of the expression of the Drosophila homolog of human NXT1, by using RNA interference, results in the nuclear accumulation of poly(A)(+) RNA in cultured insect cells. These data suggest that NXT1 may act as a molecular switch that regulates the ability of Tap to mediate nuclear mRNA export by controlling the interaction of Tap with components of the nuclear pore.</p>
},
  year = {2002},
  journal = {Mol Cell Biol},
  volume = {22},
  pages = {245-56},
  month = {01/2002},
  issn = {0270-7306},
  language = {eng},
}