Mitofusins, conserved dynamin-related GTPases in the mitochondrial outer membrane, mediate the fusion of mitochondria. Here, we demonstrate that the activity of the mitofusin Fzo1 is regulated by sequential ubiquitylation at conserved lysine residues and by the deubiquitylases Ubp2 and Ubp12. Ubp2 and Ubp12 recognize distinct ubiquitin chains on Fzo1 that have opposing effects on mitochondrial fusion. Ubp2 removes ubiquitin chains that initiate proteolysis of Fzo1 and inhibit fusion. Ubp12 recognizes ubiquitin chains that stabilize Fzo1 and promote mitochondrial fusion. Self-assembly of dynamin-related GTPases is critical for their function. Ubp12 deubiquitylates Fzo1 only after oligomerization. Moreover, ubiquitylation at one monomer activates ubiquitin chain formation on another monomer. Thus, regulation of mitochondrial fusion involves ubiquitylation of mitofusin at distinct lysine residues, intermolecular crosstalk between mitofusin monomers, and two deubiquitylases that act as regulatory and quality control enzymes.
|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||Annotation Extension||Reference|
|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||Assay||Construct||Conditions||Strain Background||Reference|