| First Author | Stokka AJ | Year | 2009 |
| Journal | Biochem J | Volume | 425 |
| Issue | 2 | Pages | 381-8 |
| PubMed ID | 19857202 | Mgi Jnum | J:170137 |
| Mgi Id | MGI:4944038 | Doi | 10.1042/BJ20091136 |
| Citation | Stokka AJ, et al. (2010) The adaptor protein EBP50 is important for localization of the protein kinase A-Ezrin complex in T-cells and the immunomodulating effect of cAMP. Biochem J 425(2):381-8 |
| abstractText | We recently reported that the dual-specificity AKAP (A-kinaseanchoring protein) Ezrin targets type I PKA (protein kinase A) to the vicinity of the TCR (T-cell receptor) in T-cells and, together with PAG (phosphoprotein associated with glycosphingolipid-enriched membrane microdomains) and EBP50 [ERM (Ezrin/Radixin/Moesin)-binding phosphoprotein 50], forms a scaffold that positions PKA close to its substrate, Csk (C-terminal Src kinase). This complex is important for controlling the activation state of T-cells. Ezrin binds the adaptor protein EBP50, which again contacts PAG. In the present study, we show that Ezrin and EBP50 interact with high affinity (KD=58+/-7 nM). A peptide corresponding to the EB (Ezrin-binding) region in EBP50 (EBP50pep) was used to further characterize the binding kinetics and compete the Ezrin-EBP50 interaction by various methods in vitro. Importantly, loading T-cells with EBP50pep delocalized Ezrin, but not EBP50. Furthermore, disruption of this complex interfered with cAMP modulation of T-cell activation, which is seen as a reversal of cAMP-mediated inhibition of IL-2 (interleukin 2) production, demonstrating an important role of EBP50 in this complex. In summary, both the biochemical and functional data indicate that targeting the Ezrin-EBP interaction could be a novel and potent strategy for immunomodulation. |
