El próximo lunes 6 de octubre tenemos a Ivan Plaza-Menacho que impartirá un seminario en la sala 300 a las 12:00:
Molecular mechanisms of RET tyrosine kinase cis-regulation and oncogenic deregulation in trans: implications for targeted therapy
Ivan Plaza-Menacho, Structural Biology Laboratory, London Research Institute, Cancer Research UK
To decipher the molecular basis for RET kinase activation and oncogenic deregulation we defined the temporal sequence of RET autophosphorylation by label-free quantitative mass spectrometry (LFQMS). Early autophosphorylation sites map to regions flanking the kinase domain core, whilst sites within the activation loop only form at later time-points. Comparison with oncogenic RET kinase revealed that late autophosphorylation sites become phosphorylated much earlier than wild-type RET, which is due to a combination of an enhanced enzymatic activity, increased ATP affinity and, surprisingly, by providing a better intermolecular substrate. Structural analysis of oncogenic M918T and wild-type RET kinase domains reveal a cis-inhibitory mechanism precluding ATP-binding involving tethering contacts between the glycine-rich loop, activation loop and aC helix. In solution disruption of such tether by oncogenic RET kinase is favored by an extended activation loop conformer. These results reveal an underappreciated role for oncogenic RET kinase mutations in promoting intermolecular autophosphorylation by enhancing substrate presentation in trans [1]. Furthermore these data also pointed at the importance of autophosphorylation sites outside the RET kinase domain core prior to activation loop phosphorylation, indicating an allosteric component to RET kinase activation and regulation. In this line, biochemical and structural evidence for an allosteric input by the juxtamembrane region enhancing RET kinase domain activity is also provided. Altogether these data are crucial the design and development of more potent and specific RET kinase inhibitors (i.e. allosteric compounds) which should be at the forefront of the new therapeutic strategies for patients with RET-driven tumors.
[1] Plaza-Menacho I, Barnouin K, Goodman K, Martínez-Torres RJ, Borg A, Murray-Rust J, Mouilleron S, Knowles P, McDonald NQ. Oncogenic RET kinase domain mutations perturb the autophosphorylation trajectory by enhancing substrate presentation in trans. Mol Cell. 2014 Mar 6;53(5):738-51. doi: 10.1016/j.molcel.2014.01.015. Epub 2014 Feb 20.
