David Komander is a biochemist and cell biologist, and a recognised leader in the field of ubiquitylation. He generated new tools to unveil the complexity and specificity of the ubiquitin code, and uncovered fundamental principles in ubiquitin chain assembly, recognition and disassembly by deubiquitylating enzymes (DUBs). Komander discovered OTULIN, a specialised DUB in inflammation, and described the human monogenic disease OTULIN-related autoinflammatory syndrome (ORAS). He determined the molecular basis for PINK1/Parkin-mediated mitophagy, a key ubiquitylation pathway derailed in inherited Parkinson’s disease. His ultimate aim is the development of the first disease-modifying therapies for Parkinson’s and other ubiquitin-based disorders.