Regulation of C-type lectin antimicrobial activity by a flexible N-terminal prosegment

J Biol Chem. 2009 Feb 20;284(8):4881-8. doi: 10.1074/jbc.M808077200. Epub 2008 Dec 18.


Members of the RegIII family of intestinal C-type lectins are directly antibacterial proteins that play a vital role in maintaining host-bacterial homeostasis in the mammalian gut, yet little is known about the mechanisms that regulate their biological activity. Here we show that the antibacterial activities of mouse RegIIIgamma and its human ortholog, HIP/PAP, are tightly controlled by an inhibitory N-terminal prosegment that is removed by trypsin in vivo. NMR spectroscopy revealed a high degree of conformational flexibility in the HIP/PAP inhibitory prosegment, and mutation of either acidic prosegment residues or basic core protein residues disrupted prosegment inhibitory activity. NMR analyses of pro-HIP/PAP variants revealed distinctive colinear backbone amide chemical shift changes that correlated with antibacterial activity, suggesting that prosegment-HIP/PAP interactions are linked to a two-state conformational switch between biologically active and inactive protein states. These findings reveal a novel regulatory mechanism governing C-type lectin biological function and yield new insight into the control of intestinal innate immunity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / immunology
  • Anti-Bacterial Agents / metabolism
  • Antigens, Neoplasm / chemistry*
  • Antigens, Neoplasm / immunology
  • Antigens, Neoplasm / metabolism
  • Biomarkers, Tumor / chemistry*
  • Biomarkers, Tumor / immunology
  • Biomarkers, Tumor / metabolism
  • Homeostasis / physiology*
  • Humans
  • Immunity, Innate / physiology
  • Intestinal Mucosa / metabolism
  • Intestines / chemistry
  • Intestines / immunology
  • Lectins, C-Type / chemistry*
  • Lectins, C-Type / immunology
  • Lectins, C-Type / metabolism
  • Mice
  • Mice, Knockout
  • Nuclear Magnetic Resonance, Biomolecular
  • Pancreatitis-Associated Proteins
  • Protein Structure, Secondary / physiology
  • Protein Structure, Tertiary / physiology
  • Proteins / chemistry*
  • Proteins / immunology
  • Proteins / metabolism


  • Anti-Bacterial Agents
  • Antigens, Neoplasm
  • Biomarkers, Tumor
  • Lectins, C-Type
  • Pancreatitis-Associated Proteins
  • Proteins
  • REG3A protein, human
  • Reg3g protein, mouse