Bactericidal C-type lectin which acts exclusively against Gram-positive bacteria and mediates bacterial killing by binding to surface-exposed carbohydrate moieties of peptidoglycan. Restricts bacterial colonization of the intestinal epithelial surface and consequently limits activation of adaptive immune responses by the microbiota. The uncleaved form has bacteriostatic activity, whereas the cleaved form has bactericidal activity against L.monocytogenes and methicillin-resistant S.aureus. Regulates keratinocyte proliferation and differentiation after skin injury. Predominantly expressed in the small intestine, including Paneth cells (at protein level). Hardly detectable in the colon (at protein level). Highly expressed in the lung epithelium during methicillin-resistant S.aureus infection (at protein level). Skin injury increases its epidermal expression. Also expressed in the pancreas. In mid-small intestine, very low levels at birth. Expression levels rise dramatically during the weaning period (P17-P22) and remain high into adulthood in conventionally raised but not germfree animals. Up-regulated in Paneth cells by intestinal microbiota (at protein level). MyD88-mediated signals are essential for its induction in intestinal epithelial cells. Induction in the lung is dependent on IL6ST-induced STAT3 signaling. IL17A induces its expression in primary keratinocytes and skin wounds. The EPN motif is essential for recognition of the peptidoglycan carbohydrate backbone and for efficient bacterial killing with Glu-114 playing a key role in peptidoglycan binding and bactericidal activity. Proteolytic processing by trypsin removes an inhibitory N-terminal propeptide and is essential for peptidoglycan binding and antibacterial activity. Mutant mice are born at normal Mendelian ratios. They appear healthy and show no signs of enteropathy, but exhibit a marked increase in the number of mucosa-associated bacteria, predominantly Gram-positive, relative to cohoused wild-type littermates in distal small intestine.