title: Tuning protein autoinhibition by domain destabilization.
abstract: Activation of many multidomain signaling proteins requires rearrangement of autoinhibitory interdomain interactions that occlude activator binding sites. In one model for activation, the major inactive conformation exists in equilibrium with activated-like conformations that can be stabilized by ligand binding or post-translational modifications. We established the molecular basis for this model for the archetypal signaling adaptor protein Crk-II by measuring the thermodynamics and kinetics of the equilibrium between autoinhibited and activated-like states. We used fluorescence and NMR spectroscopies together with segmental isotopic labeling by means of expressed protein ligation. The results demonstrate that intramolecular domain-domain interactions both stabilize the autoinhibited state and induce the activated-like conformation. A combination of favorable interdomain interactions and unfavorable intradomain structural changes fine-tunes the population of the activated-like conformation and allows facile response to activators. This mechanism suggests a general strategy for optimization of autoinhibitory interactions of multidomain proteins.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA.
authors.forename: Jae-Hyun
authors.initials: JH
authors.lastname: Cho
authors.forename: Vasant
authors.initials: V
authors.lastname: Muralidharan
authors.forename: Miquel
authors.initials: M
authors.lastname: Vila-Perello
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Raleigh
authors.forename: Tom W
authors.initials: TW
authors.lastname: Muir
authors.forename: Arthur G
authors.initials: AG
authors.lastname: Palmer
mesh_terms: D001665:Binding Sites; D007700:Kinetics; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D017510:Protein Folding; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D050737:Proto-Oncogene Proteins c-crk / Q000737:chemistry* / Q000235:genetics; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: D050737:Proto-Oncogene Proteins c-crk