title: Regulation of C-type lectin antimicrobial activity by a flexible N-terminal prosegment.
abstract: 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.
authors.affiliation: Department of Immunology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
authors.forename: Sohini
authors.initials: S
authors.lastname: Mukherjee
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Partch
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Lehotzky
authors.forename: Cecilia V
authors.initials: CV
authors.lastname: Whitham
authors.forename: Hiutung
authors.initials: H
authors.lastname: Chu
authors.forename: Charles L
authors.initials: CL
authors.lastname: Bevins
authors.forename: Kevin H
authors.initials: KH
authors.lastname: Gardner
authors.forename: Lora V
authors.initials: LV
authors.lastname: Hooper
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D000951:Antigens, Neoplasm / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D007113:Immunity, Innate / Q000502:physiology; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000737:chemistry / Q000276:immunology; D037181:Lectins, C-Type / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D019906:Nuclear Magnetic Resonance, Biomolecular; D000073718:Pancreatitis-Associated Proteins; D017433:Protein Structure, Secondary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011506:Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D037181:Lectins, C-Type; D000073718:Pancreatitis-Associated Proteins; D011506:Proteins; C000612141:REG3A protein, human; C490255:Reg3g protein, mouse