Identification of Novel Import and Export Signals of Human TAP, the Protein That Binds to the Constitutive Transport Element of the Type D Retrovirus mRNAs
| Autor: | Jenifer Bear, Carlos Tabernero, Wei Tan, Barbara K. Felber, Andrei S. Zolotukhin, Eric A. Hudson |
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| Rok vydání: | 1999 |
| Předmět: |
Nuclear Envelope
Recombinant Fusion Proteins Molecular Sequence Data Nuclear Localization Signals Biological Transport Active Gene Expression Plasma protein binding Biology Betaretrovirus Cell Line NXF1 Mice Open Reading Frames Xenopus laevis Animals Humans NLS Amino Acid Sequence RNA Messenger ATP Binding Cassette Transporter Subfamily B Member 2 Nuclear protein Nuclear export signal Molecular Biology Binding Sites Nucleoplasm Sequence Homology Amino Acid Cell Biology Molecular biology Rats Cell biology Cytoplasm RNA Viral ATP-Binding Cassette Transporters Nuclear transport HeLa Cells Protein Binding |
| Zdroj: | Molecular and Cellular Biology. 19:6306-6317 |
| ISSN: | 1098-5549 |
| Popis: | The nuclear export of the unspliced type D retrovirus mRNA depends on the cis-acting constitutive transport RNA element (CTE) that has been shown to interact with the human TAP (hTAP) protein promoting the export of the CTE-containing mRNAs. We report here that hTAP is a 619-amino-acid protein extending the previously identified protein by another 60 residues at the N terminus and that hTAP shares high homology with the predicted rat and mouse TAP proteins. We found that hTAP is a nuclear protein that accumulates in the nuclear rim and the nucleoplasm. We further demonstrated that hTAP is able to shuttle between the nucleus and the cytoplasm. Identification of the signals responsible for nuclear import (NLS) and export (NES) revealed that they are distinct but partially overlapping. NLS and NES of hTAP are active transferable signals that do not share similarities with known elements. The C-terminal portion contributes further to hTAP’s nuclear retention and contains a signal(s) for nuclear rim association. Taken together, our data show that hTAP is a dynamic protein capable of bidirectional trafficking across the nuclear envelope. These data further support hTAP’s role as an export factor of the CTE-containing mRNAs. |
| Databáze: | OpenAIRE |
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