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Phosphorylation-induced conformational changes in Rap1b: allosteric effects on switch domains and effector loop.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2009 Oct 02; Vol. 284 (40), pp. 27480-6. Date of Electronic Publication: 2009 Aug 03. - Publication Year :
- 2009
-
Abstract
- 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 Ser(179) 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 Ser(179) 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.
Details
- Language :
- English
- ISSN :
- 1083-351X
- Volume :
- 284
- Issue :
- 40
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 19651783
- Full Text :
- https://doi.org/10.1074/jbc.M109.011312