| First Author | Chen TH | Year | 1996 |
| Journal | Mol Biol Cell | Volume | 7 |
| Issue | 12 | Pages | 2045-56 |
| PubMed ID | 8970164 | Mgi Jnum | J:37303 |
| Mgi Id | MGI:84705 | Doi | 10.1091/mbc.7.12.2045 |
| Citation | Chen TH, et al. (1996) Structure of pp32, an acidic nuclear protein which inhibits oncogene-induced formation of transformed foci. Mol Biol Cell 7(12):2045-56 |
| abstractText | pp32 is a nuclear protein found highly expressed in normal tissues in those cells capable of self-renewal and in neoplastic cells. We report the cloning of cDNAs encoding human and murine pp32. The clones encode a 28.6-kDa protein; approximately two-thirds of the N-terminal predicts an amphipathic alpha helix containing two possible nuclear localization signals and a potential leucine zipper motif. The C-terminal third is exceptionally acidic, comprised of approximately 70% aspartic and glutamic acid residues; the predicted pI of human pp32 is 3.81. Human and murine pp32 cDNAs are 88% identical; the predicted proteins are 89% identical and 95% similar. Although the structure of pp32 is suggestive of a transcription factor, pp32 did not significantly modulate transcription of a reporter construct when fused to the Gal4 DNA-binding domain. In contrast, in cotransfection experiments, pp32 inhibited the ability of a broad assortment of oncogene pairs to transform rat embryo fibroblasts, including ras + myc, ras + jun, ras + E1a, ras + mutant p53, and E6 + E7. In related experiments, pp32 inhibited the ability of Rat 1a-myc cells to grow in soft agar, whereas it failed to affect ras-induced focus formation in NIH3T3 cells. These results suggest that pp32 may play a key role in self-renewing cell populations where it may act in the nucleus to limit their sensitivity to transformation. |
