Coordinated expression of BP1026B_II1561, BP1026B_II1815 (trpA), and BP1026B_II1817 (trpB) as Bp protrudes towards neighboring host cells suggests that tryptophan biosynthesis is also important during intracellular infection (Heacock-Kang et al., 2021). Here, TPSG1 is linked to infection.