| First Author | Braun KR | Year | 2012 |
| Journal | PLoS One | Volume | 7 |
| Issue | 8 | Pages | e43701 |
| PubMed ID | 22912899 | Mgi Jnum | J:189972 |
| Mgi Id | MGI:5447597 | Doi | 10.1371/journal.pone.0043701 |
| Citation | Braun KR, et al. (2012) Inhibition of PDGF-B induction and cell growth by syndecan-1 involves the ubiquitin and SUMO-1 ligase, Topors. PLoS One 7(8):e43701 |
| abstractText | Syndecans are receptors for soluble ligands, including heparin-binding growth factors, and matrix proteins. However, intracellular targets of syndecan-1 (Sdc-1)-mediated signaling are not fully understood. A yeast two-hybrid protein interaction screening of a mouse embryo library identified the ubiquitin and SUMO-1 E3 ligase, Topors, as a novel ligand of the Sdc-1 cytoplasmic domain (S1CD), a finding confirmed by ligand blotting and co-precipitation with Sdc-1 from cell lysates. Deletion mutagenesis identified an 18-amino acid sequence of Topors required for the interaction with the S1CD. By immunohistochemistry, Topors and Sdc-1 co-localized near the cell periphery in normal murine mammary gland (NMuMG) cells in vitro and in mouse embryonic epithelia in vivo. Finally, siRNA-mediated knockdown of Topors demonstrated that Topors is a growth promoter for murine arterial smooth muscle cells and is required for the inhibitory effect of Sdc-1 on cell growth and platelet-derived growth factor-B induction. These data suggest a novel mechanism for the inhibitory effects of Sdc-1 on cell growth that involves the interaction between the cytoplasmic domain of Sdc-1 and the SUMO-1 E3 ligase, Topors. |
