| First Author | Janoueix-Lerosey I | Year | 1998 |
| Journal | Eur J Biochem | Volume | 252 |
| Issue | 2 | Pages | 290-8 |
| PubMed ID | 9523700 | Mgi Jnum | J:60992 |
| Mgi Id | MGI:1354195 | Doi | 10.1046/j.1432-1327.1998.2520290.x |
| Citation | Janoueix-Lerosey I, et al. (1998) Identification of a specific effector of the small GTP-binding protein Rap2. Eur J Biochem 252(2):290-8 |
| abstractText | Rap2 is a small GTP-binding protein that belongs to the Ras superfamily and whose function is still unknown. To elucidate Rap2 function, we searched for potential effectors by screening a mouse brain cDNA library in a yeast two-hybrid system using as a bait a Rap2A protein bearing a mutation of Gly to Val at position 12. This strategy lead to the identification of a protein that interacts specifically with Rap2A complexed with GTP, and requires an intact effector domain of Rap2A for interaction; we designated this protein Rap2-interacting protein 8 (RPIP8). Biochemical data obtained from in vitro studies with purified proteins confirmed the genetic results. Mouse RPIP8 consists of 446 amino acids, bears a coiled-coil domain between residues 265 and 313, and is expressed principally in brain. Its human counterpart, of 400 amino acids, exhibits 93.7% identity in their common region. A search for similar sequences in expressed-sequence-tags databanks revealed the presence in human and rodents of mRNAs encoding the 400-residue and 446-residue forms of RPIP8. Furthermore a doublet of 45-50 kDa, corresponding to the 400-residue and 446-residue forms of the protein, was detected by western blotting of mouse brain extracts and lysates from pheochromocytoma PC12 cells and the pancreatic beta-cell lines HIT-T15 and RIN-m5F. Using transient transfections of HIT-T15 cells it was possible to demonstrate that [Val12]Rap2 and wild-type Rap2 could be immunoprecipitated with RPIP8. These data therefore argue for RPIP8 being a specific effector of the Rap2 protein in cells exhibiting neuronal properties. |
