16
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Classification, structural biology, and applications of mucin domain-targeting proteases

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Epithelial surfaces throughout the body are coated by mucins, a class of proteins carrying domains characterized by a high density of O-glycosylated serine and threonine residues. The resulting mucosal layers form crucial host-microbe interfaces that prevent the translocation of microbes while also selecting for distinct bacteria via the presented glycan repertoire. The intricate interplay between mucus production and breakdown thus determines the composition of the microbiota maintained within these mucosal environments, which can have a large influence on the host during both homeostasis and disease. Most research to date on mucus breakdown has focused on glycosidases that trim glycan structures to release monosaccharides as a source of nutrients. More recent work has uncovered the existence of mucin-type O-glycosylation-dependent proteases that are secreted by pathogens, commensals, and mutualists to facilitate mucosal colonization and penetration. Additionally, immunoglobulin A (IgA) proteases promote bacterial colonization in the presence of neutralizing secretory IgA through selective cleavage of the heavily O-glycosylated hinge region. In this review, we summarize families of O-glycoproteases and IgA proteases, discuss known structural features, and review applications of these enzymes to glycobiology.

          Related collections

          Most cited references138

          • Record: found
          • Abstract: found
          • Article: not found

          A Dietary Fiber-Deprived Gut Microbiota Degrades the Colonic Mucus Barrier and Enhances Pathogen Susceptibility.

          Despite the accepted health benefits of consuming dietary fiber, little is known about the mechanisms by which fiber deprivation impacts the gut microbiota and alters disease risk. Using a gnotobiotic mouse model, in which animals were colonized with a synthetic human gut microbiota composed of fully sequenced commensal bacteria, we elucidated the functional interactions between dietary fiber, the gut microbiota, and the colonic mucus barrier, which serves as a primary defense against enteric pathogens. We show that during chronic or intermittent dietary fiber deficiency, the gut microbiota resorts to host-secreted mucus glycoproteins as a nutrient source, leading to erosion of the colonic mucus barrier. Dietary fiber deprivation, together with a fiber-deprived, mucus-eroding microbiota, promotes greater epithelial access and lethal colitis by the mucosal pathogen, Citrobacter rodentium. Our work reveals intricate pathways linking diet, the gut microbiome, and intestinal barrier dysfunction, which could be exploited to improve health using dietary therapeutics.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Gut biogeography of the bacterial microbiota.

            Animals assemble and maintain a diverse but host-specific gut microbial community. In addition to characteristic microbial compositions along the longitudinal axis of the intestines, discrete bacterial communities form in microhabitats, such as the gut lumen, colonic mucus layers and colonic crypts. In this Review, we examine how the spatial distribution of symbiotic bacteria among physical niches in the gut affects the development and maintenance of a resilient microbial ecosystem. We consider novel hypotheses for how nutrient selection, immune activation and other mechanisms control the biogeography of bacteria in the gut, and we discuss the relevance of this spatial heterogeneity to health and disease.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              The two mucus layers of colon are organized by the MUC2 mucin, whereas the outer layer is a legislator of host-microbial interactions.

              The normal intestinal microbiota inhabits the colon mucus without triggering an inflammatory response. The reason for this and how the intestinal mucus of the colon is organized have begun to be unraveled. The mucus is organized in two layers: an inner, stratified mucus layer that is firmly adherent to the epithelial cells and approximately 50 μm thick; and an outer, nonattached layer that is usually approximately 100 μm thick as measured in mouse. These mucus layers are organized around the highly glycosylated MUC2 mucin, forming a large, net-like polymer that is secreted by the goblet cells. The inner mucus layer is dense and does not allow bacteria to penetrate, thus keeping the epithelial cell surface free from bacteria. The inner mucus layer is converted into the outer layer, which is the habitat of the commensal flora. The outer mucus layer has an expanded volume due to proteolytic activities provided by the host but probably also caused by commensal bacterial proteases and glycosidases. The numerous O-glycans on the MUC2 mucin not only serve as nutrients for the bacteria but also as attachment sites and, as such, probably contribute to the selection of the species-specific colon flora. This observation that normal human individuals carry a uniform MUC2 mucin glycan array in colon may indicate such a specific selection.
                Bookmark

                Author and article information

                Contributors
                (View ORCID Profile)
                (View ORCID Profile)
                (View ORCID Profile)
                (View ORCID Profile)
                Journal
                Biochemical Journal
                Portland Press Ltd.
                0264-6021
                1470-8728
                April 30 2021
                April 30 2021
                April 28 2021
                : 478
                : 8
                : 1585-1603
                Affiliations
                [1 ]Department of Chemistry and Stanford ChEM-H, Stanford University, Stanford, CA 94305, U.S.A.
                [2 ]Department of Chemistry, University of Redlands, Redlands, CA 92373, U.S.A.
                [3 ]Department of Chemistry, Yale University, New Haven, CT 06511, U.S.A.
                Article
                10.1042/BCJ20200607
                33909028
                fc8bd316-4a45-47d3-98c2-96e12ac4e5f7
                © 2021
                History

                Comments

                Comment on this article