Macrophages are white blood cells that perform different functions with different energy needs. M2-type macrophages have anti-inflammatory properties that may protect against inflammatory disorders such as inflammatory bowel disease (IBD). However, the molecular pathways driving M2 formation are not fully understood. Researchers identified a protein commonly involved in nervous system development that plays a key role in metabolism of M2 macrophages and protecting against colitis symptoms in mice. The findings may lead to new therapeutic targets for inflammatory diseases.