T lymphocytes are a critical component of the adaptive immune system and provide specific protection against pathogens and cancer cells. Defects in T cell activation or migration lead to primary immunodeficiency diseases, characterized by increased susceptibility to viral and bacterial infections. However, T cell hyperactivity can result in autoimmune attack of one’s own tissue. The quality and magnitude of a T cell response are controlled by positive and negative cues from the T cell microenvironment. We investigate how T cells appropriately and inappropriately translate activation and migration cues.