Abstract:Bacterial protein secretion is an important way of cell-cell interaction between species, which plays a crucial role in interbacterial competition and pathogenesis. Gram-negative bacteria could use the type VI secretion system (T6SS) to deliver effector proteins to the extracellular environment or prokaryotic and eukaryotic cells, thereby promoting their fitness during competition between microorganisms or host-microbe interactions. This paper summarizes the latest advances in the structures and components of T6SS, with focus on effector assembly and effector-immunity pairs, providing new strategies for the development of antibacterial drugs in the future.