Gut bactericidal protein that selectively kills Gram-positive bacteria by binding to negatively charged lipids on bacterial membranes, leading to bacterial membrane permeabilization and disruption. Specifically binds lipids bearing negatively charged headgroups, such as phosphatidic acid, phosphatidylserine (PS), cardiolipin (CL), and phosphatidylinositol phosphates, but not to zwitterionic or neutral lipids. Induced by type-2 cytokines in response to helminth infection and is required to protect against helminth-induced bacterial invasion of intestinal tissue. May also be involved in the development of the cornified envelope of squamous epithelia; however, additional evidences are required to confirm this result in vivo 