Immunity component of one of 6 LXG toxin-immunity modules in this strain. They promote kin selection, mediate competition in biofilms, and drive spatial segregation of different strains, indicating that LXG toxins may help avoid warfare between strains in biofilms. Mediates intercellular competition during biofilm formation; disruption of the operon disadvantages the bacteria, but overexpression of the cognate immunity protein restores growth in competition with wild-type. In situ neutralizes the toxic effect of cognate toxin YokI (PubMed:34280190). Neutralizes the ability to inhibit growth of cognate toxin YokI upon expression in E.coli. Does not have immunity protein activity on other LXG toxins (PubMed:22200572). Probably interacts with cognate toxin YokI but not with other non-cognate toxins. The interaction inhibits the toxic activity of YokI (Probable). Expressed on rich and minimal solid media likely in early stationary phase; not dependent on DegSU. Not expressed in liquid LB, but only under conditions that promote biofilm formation. Deletion of the yokI-yokJ operon has no visible growth phenotype, however it is out-competed by wild-type cells.