Disease relevance of Cd209b

• Specific ICAM-3 grabbing nonintegrin-related 1 (SIGNR1) expressed by marginal zone macrophages is essential for defense against pulmonary Streptococcus pneumoniae infection [1].
• To better understand the mechanism by which DC-SIGN and DC-SIGNR selectively bind HIV-1 gp120, we constructed a series of deletion mutations in the repeat regions of both receptors [2].

High impact information on Cd209b

• Moreover, mSIGNR1 is also expressed by medullary and subcapsular macrophages in lymph nodes and by marginal zone macrophages (MZMs) in the spleen [3].
• We demonstrate here that mSIGNR1 functions in vivo as a pathogen recognition receptor on MZMs that capture blood-borne antigens, which are rapidly internalized and targeted to lysosomes for processing [3].
• The finding that neither SIGNR1 nor SIGNR5 binds with high affinity to specific ligands in a large panel of mammalian glycans is consistent with the suggestion that these receptors bind surface polysaccharides on bacterial and fungal pathogens in a manner analogous to serum mannose-binding protein [4].
• In addition to five SIGNR proteins previously described, a pseudogene, encoding a hypothetical SIGNR6, and a further two expressed proteins, SIGNR7 and SIGNR8, have been identified [4].
• However, in the nonprofessional phagocytes (NIH3T3), SIGNR1 was found to be poorly phagocytic, suggesting that other receptors such as betaGR may play a more dominant role in particle internalization on professional phagocytes [5].

Biological context of Cd209b

• However, SIGNR1 is not expressed by alveolar macrophages, suggesting that another mechanism than a decrease in phagocytosis is responsible for this difference [1].
• We demonstrate that marginal zone macrophages from SIGNR1-deficient mice in contrast to wild-type mice are not able to capture pneumococci from blood, suggesting that SIGNR1 on marginal zone macrophages captures S. pneumoniae for antigen presentation to and activation of marginal zone B cells, resulting in an anti-phosphorylcholine IgM response [1].

Anatomical context of Cd209b

• The role of SIGNR1 and the beta-glucan receptor (dectin-1) in the nonopsonic recognition of yeast by specific macrophages [5].
• When SIGNR1 was introduced into NIH3T3 fibroblasts or RAW 264.7 Mphi, it conferred marked zymosan-binding potential on these cells [5].
• The dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN) homolog, SIGN-related 1 (SIGNR1) is a pathogen receptor expressed by splenic marginal zone and peritoneal macrophages, and is essential for clearance of Streptococcus pneumoniae by phagocytosis after intraperitoneal infection [1].
• We first used transfected non-macrophage cell lines to compare the polysaccharide and microbial uptake capacities of three of these lectins--DC-SIGN, SIGNR1 and SIGNR3--to another homologue mLangerin [6].

Associations of Cd209b with chemical compounds

• In this study, we have studied the mannose-binding potential of murine Mphi and identified the dendritic cell-specific ICAM-3-grabbing nonintegrin homolog, SIGN-related 1 (SIGNR1), as a major MR on murine resident peritoneal Mphi [5].
• In addition, resident peritoneal CD11b+ cells expressing SIGNR1 bound zymosan at 4 degrees C in concert with a laminarin-sensitive receptor [6].
• Interestingly, transfectants with SIGNR1 lacking the cytoplasmic domain were capable of binding FITC-zymosan in a manner that was abolished by EDTA or mannan, but not laminarin [6].

References