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Title | Architecture of autoinhibited and active BRAF-MEK1-14-3-3 complexes. |
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Journal, issue, pages | Nature, Vol. 575, Issue 7783, Page 545-550, Year 2019 |
Publish date | Oct 3, 2019 |
Authors | Eunyoung Park / Shaun Rawson / Kunhua Li / Byeong-Won Kim / Scott B Ficarro / Gonzalo Gonzalez-Del Pino / Humayun Sharif / Jarrod A Marto / Hyesung Jeon / Michael J Eck / |
PubMed Abstract | RAF family kinases are RAS-activated switches that initiate signalling through the MAP kinase cascade to control cellular proliferation, differentiation and survival. RAF activity is tightly ...RAF family kinases are RAS-activated switches that initiate signalling through the MAP kinase cascade to control cellular proliferation, differentiation and survival. RAF activity is tightly regulated and inappropriate activation is a frequent cause of cancer; however, the structural basis for RAF regulation is poorly understood at present. Here we use cryo-electron microscopy to determine autoinhibited and active-state structures of full-length BRAF in complexes with MEK1 and a 14-3-3 dimer. The reconstruction reveals an inactive BRAF-MEK1 complex restrained in a cradle formed by the 14-3-3 dimer, which binds the phosphorylated S365 and S729 sites that flank the BRAF kinase domain. The BRAF cysteine-rich domain occupies a central position that stabilizes this assembly, but the adjacent RAS-binding domain is poorly ordered and peripheral. The 14-3-3 cradle maintains autoinhibition by sequestering the membrane-binding cysteine-rich domain and blocking dimerization of the BRAF kinase domain. In the active state, these inhibitory interactions are released and a single 14-3-3 dimer rearranges to bridge the C-terminal pS729 binding sites of two BRAFs, which drives the formation of an active, back-to-back BRAF dimer. Our structural snapshots provide a foundation for understanding normal RAF regulation and its mutational disruption in cancer and developmental syndromes. |
External links | Nature / PubMed:31581174 / PubMed Central |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 2.59 - 6.8 Å |
Structure data | EMDB-0541, PDB-6nyb: EMDB-20550, PDB-6q0j: EMDB-20551, PDB-6q0k: EMDB-20552, PDB-6q0t: PDB-6pp9: |
Chemicals | ChemComp-AGS: ChemComp-ZN: ChemComp-ADP: ChemComp-MG: ChemComp-LCJ: ChemComp-ANP: ChemComp-CL: ChemComp-SO4: ChemComp-GOL: ChemComp-HOH: |
Source |
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Keywords | TRANSFERASE / BRAF / MEK1 / Transferase/PROTEIN BINDING / Transferase-PROTEIN BINDING complex / SIGNALING PROTEIN/Transferase / SIGNALING PROTEIN-Transferase complex |