Coronin 1 is a member of the WD repeat family of coronin proteins that are widely conserved among all eukaryotes1. In lower eukaryotes such as yeast and Dictyostelium discoideum, a single coronin is expressed, while in higher vertebrates, up to seven coronin isoforms can be found that are associated with a wide array of activities, including cell motility, vesicle trafficking and tumor formation. While in Dictyostelium, coronin has been linked to phagocytosis, cytokinesis and motility, the role for coronins in higher eukaryotes has remained unclear. The closest homologue of Dictyostelium coronin in vertebrates is coronin 1 (also known as P57 or TACO, for Tryptophan Aspartate containing COat protein). Coronin 1 was originally identified by my laboratory as a protein that allows the survival of pathogenic mycobacteria within macrophages; While upon phagocytosis, non‐pathogenic bacilli are readily transferred to lysosomes and destroyed, virulent mycobacteria retain coronin 1 at the mycobacterial phagosome thereby blocking lysosomal delivery and thereby surviving within macrophage phagosomes. Subsequent work revealed an essential role for coronin 1 in the survival of T lymphocytes. Our recent work suggests that coronin 1 functions as an important regulator of signal transduction. As such, coronin 1 regulates the survival of peripheral T cells, as well as intracellular survival of Mycobacterium tuberculosis in macrophages. The proposed work aims at defining the molecular constituents of the coronin 1‐dependent signaling pathway. Given the association of coronin 1 with several disease models in mice such as tuberculosis and autoimmunity, the proposed work may contribute to a better understanding of coronin 1 in normal physiology as well as in disease.