| First Author | Wu J | Year | 1999 |
| Journal | J Biol Chem | Volume | 274 |
| Issue | 41 | Pages | 29202-10 |
| PubMed ID | 10506177 | Mgi Jnum | J:219113 |
| Mgi Id | MGI:5619496 | Doi | 10.1074/jbc.274.41.29202 |
| Citation | Wu J, et al. (1999) The quaking I-5 protein (QKI-5) has a novel nuclear localization signal and shuttles between the nucleus and the cytoplasm. J Biol Chem 274(41):29202-10 |
| abstractText | The mouse quaking (qk) gene is essential in both myelination and early embryogenesis. Its product, QKI, is an RNA-binding protein belonging to a growing protein family called STAR (signal transduction and activator of RNA). All members have an approximately 200-amino acid STAR domain, which contains a single extended heteronuclear ribonucleoprotein K homologue domain flanked by two domains called QUA1 and QUA2. We found that QKI isoforms could associate with each other, while one of the lethal mutations qkI(kt4) with a single amino acid change in QUA1 domain, leads to a loss of QKI self-interaction. This suggests that the QUA1 domain is responsible for QKI dimerization. Three QKI isoforms have different carboxyl termini and different subcellular localization. Here, using GFP fusion protein, we identified a 7-amino acid novel nuclear localization sequence in the carboxyl terminus of QKI-5, which is conserved in a subclass of STAR proteins containing SAM68 and ETLE/T-STAR. Thus, we name this motif STAR-NLS. In addition, the effects of active transcription, RNA-binding and self-interaction on QKI-5 localization were analyzed. Furthermore, using an interspecies heterokaryon assay, we found that QKI-5, but not another STAR protein ETLE, shuttles between the nucleus and the cytoplasm, which suggests that QKI-5 functions in both cell compartments. |
