Blm10, a crucial protease of eukaryotic cells, is bound to yeast proteasome core particles (CPs). Two gates, at both ends of the CP, control the access of protein substrates to the catalytic cavity of the CP. Normally, substrate access is auto-inhibited by a closed gate conformation unless regulatory complexes are bound to the CP and translocate protein substrates in an ATP-dependent manner. Here, we provide evidence that Blm10 recognizes pre-activated open gate CPs, which are assumed to exist in an equilibrium with inactive closed gate CP. Consequently, single-capped Blm10-CP shows peptide hydrolysis activity. Under conditions of disturbed CP assembly, as well as in open gate mutants, pre-activated CP or constitutively active CP, respectively, prevail. Then, Blm10 sequesters disordered and open gate CP by forming double-capped Blm10(2)-CP in which peptide hydrolysis activity is repressed. We conclude that Blm10 distinguishes between gate conformations and regulates the activation of CP.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|