First Author | Tcherkasowa AE | Year | 2002 |
Journal | J Immunol | Volume | 169 |
Issue | 9 | Pages | 5161-70 |
PubMed ID | 12391233 | Mgi Jnum | J:341411 |
Mgi Id | MGI:7539457 | Doi | 10.4049/jimmunol.169.9.5161 |
Citation | Tcherkasowa AE, et al. (2002) Interaction with factor associated with neutral sphingomyelinase activation, a WD motif-containing protein, identifies receptor for activated C-kinase 1 as a novel component of the signaling pathways of the p55 TNF receptor. J Immunol 169(9):5161-70 |
abstractText | Factor associated with neutral sphingomyelinase activation (FAN) represents a p55 TNFR (TNF-R55)-associated protein essential for the activation of neutral sphingomyelinase. By means of the yeast interaction trap system, we have identified the scaffolding protein receptor for activated C-kinase (RACK)1 as an interaction partner of FAN. Mapping studies in yeast revealed that RACK1 is recruited to the C-terminal WD-repeat region of FAN and binds to FAN through a domain located within WD repeats V to VII of RACK1. Our data indicate that binding of both proteins is not mediated by linear motifs but requires folding into a secondary structure, such as the multibladed propeller characteristic of WD-repeat proteins. The interaction of FAN and RACK1 was verified in vitro by glutathione S-transferase-based coprecipitation assays as well as in eukaryotic cells by coimmunoprecipitation experiments. Colocalization studies in transfected cells suggest that TNF-R55 forms a complex with FAN and that this complex recruits RACK1 to the plasma membrane. Furthermore, activation of N-SMase by TNF was strongly enhanced when RACK1, FAN, and a noncytotoxic TNF-R55 mutant were expressed concurrently, suggesting RACK1 as a modulator of N-SMase activation. Together, these findings implicate RACK1 as a novel component of the signaling pathways of TNF-R55. |