Signals in space: TGF-β defines where and what gut macrophages become.

Macrophages are profoundly shaped by their tissue of residence. In this issue, Jayaraman et al. (https://doi.org/10.1084/jem.20240801) show that TGF-β signaling is crucial for maintaining the identity, function, and spatial organization of long-lived intestinal macrophages, highlighting an essential component of the gut niche.