Phosphorylation-induced Conformational Changes in Rap1b: ALLOSTERIC EFFECTS ON SWITCH DOMAINS AND EFFECTOR LOOP*
AUTOR(ES)
Edreira, Martin M.
FONTE
American Society for Biochemistry and Molecular Biology
RESUMO
Rap1b has been implicated in the transduction of the cAMP mitogenic response. Agonists that increase intracellular cAMP rapidly activate (i.e. GTP binding) and phosphorylate Rap1b on Ser179 at its C terminus. cAMP-dependent protein kinase (PKA)-mediated phosphorylation of Rap1b is required for cAMP-dependent mitogenesis, tumorigenesis, and inhibition of AKT activity. However, the role of phosphorylation still remains unknown. In this study, we utilized amide hydrogen/deuterium exchange mass spectroscopy (DXMS) to assess potential conformational changes and/or mobility induced by phosphorylation. We report here DXMS data comparing exchange rates for PKA-phosphorylated (Rap1-P) and S179D phosphomimetic (Rap1-D) Rap1b proteins. Rap1-P and Rap1-D behaved exactly the same, revealing an increased exchange rate in discrete regions along the protein; these regions include a domain around the phosphorylation site and unexpectedly the two switch loops. Thus, local effects induced by Ser179 phosphorylation communicate allosterically with distal domains involved in effector interaction. These results provide a mechanistic explanation for the differential effects of Rap1 phosphorylation by PKA on effector protein interaction.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2785677Documentos Relacionados
- Phosphorylation-Induced Signal Propagation in the Response Regulator NtrC
- On the mitogenic properties of Rap1b: cAMP-induced G1/S entry requires activated and phosphorylated Rap1b
- The Corepressor mSin3A Regulates Phosphorylation-Induced Activation, Intranuclear Location, and Stability of AML1
- Modulation of cellular thermoresistance and actin filament stability accompanies phosphorylation-induced changes in the oligomeric structure of heat shock protein 27.
- Phosphorylation-Induced Dimerization of Interferon Regulatory Factor 7 Unmasks DNA Binding and a Bipartite Transactivation Domain