Global conformational rearrangements during the activation of the GDP/GTP exchange factor Vav3.
Activation of Rho/Rac GTPases during cell signaling requires the participation of GDP/GTP exchange factors of the Dbl family. Although the structure of the catalytic core of Dbl proteins has been established recently, the molecular changes that the full-length proteins experience during normal or oncogenic conditions of stimulation are still unknown. Here, we have used single-particle electron microscopy to solve the structures of the inactive (unphosphorylated), active (phosphorylated), and constitutively active (N-terminally deleted) versions of the exchange factor Vav3. Comparison of these forms has revealed the interdomain interactions maintaining the inactive Vav3 state and the dynamic changes that the overall Vav3 structure undergoes upon tyrosine phosphorylation. We have also found that the conformations of phosphorylated Vav3 and N-terminally deleted Vav3 are distinct, indicating that the acquisition of constitutive activity by exchange factors is structurally more complex than the mere elimination of inhibitory interactions between structural domains.
Llorca
Oscar
O
Centro de Investigaciones Biológicas, CSIC, Madrid, Spain.
Arias-Palomo
Ernesto
E
Zugaza
José L
JL
Bustelo
Xosé R
XR
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics*; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D005982:Glutathione Transferase; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics*; D007091:Image Processing, Computer-Assisted; D051379:Mice; D008854:Microscopy, Electron; D008958:Models, Molecular; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D011487:Protein Conformation; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051567:Proto-Oncogene Proteins c-vav; D018411:Spodoptera; D014443:Tyrosine / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D020662:Guanine Nucleotide Exchange Factors; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; C402726:Sh2d2a protein, mouse; C496619:Vav1 protein, mouse; C496622:Vav3 protein, mouse; D014443:Tyrosine; D005982:Glutathione Transferase