Rv3849

Rv3849, also called ESX-1-secreted protein regulator (EspR), is a key regulator of Mycobacterium tuberculosis with a size of about 14.7kDa, which can transfer bacterial proteins to host cells during infection and promote the survival of mycobacterium tuberculosis in macrophages. EspR binds to the Rv3616c-Rv3614c (EspACD) operon and activates its own transcription, and the expression product activates the secretion of the ESX-1 system. Interestingly, the EspR protein itself is also secreted outside the bacteria by the ESX-1 system, which regulates the activity of the ESX-1 secretion system in a negative feedback manner. Exogenous regulation of protein activity is not common in bacteria, so EspR proteins secreted outside the bacteria may have other functions in the host cell. At present, whether there is interaction between EspR protein and host cells and how the mechanism of action is established are not clear. If EspR has a role in inhibiting host immune function, it may become a new target for tuberculosis drug development. Therefore, exploring and studying the function of EspR in host cells has become a research hotspot in recent years.