Characterization of the Sialic Acid-binding Site in Sialoadhesin by Site-directed Mutagenesis

Vinson, Mary; Merwe, P. Anton van der; Kelm, Sørge; May, Andrew P.; Jones, E Y; Crocker, Paul R.

doi:10.1074/jbc.271.16.9267

Cited by 135 publications

(125 citation statements)

References 49 publications

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“…A point mutation at the conserved arginine residue (R114A) abolished this binding, proving that this arginine residue is essential in sialic acid recognition by this molecule (Fig. 2), as has been shown in all other Siglecs studied to date (6,16,18,(25)(26)(27)(28). Unlike some previously reported Siglecs, pretreatment of the COS cells was not essential to liberate the cell surface Siglec from masking by cisligands (Fig.…”

Section: Cloning Of a Novel Msiglec Cdna-a Partial Mouse Estsupporting

confidence: 70%

Cloning and Characterization of a Novel Mouse Siglec, mSiglec-F

Angata¹,

Hingorani²,

Varki³

et al. 2001

Journal of Biological Chemistry

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A novel mouse Siglec (mSiglec-F) belonging to the subfamily of Siglec-3-related Siglecs has been cloned and characterized. Unlike most human Siglec-3 (hSiglec-3)-related Siglecs with promiscuous linkage specificity, mSiglec-F shows a strong preference for ␣2-3-linked sialic acids. It is predominantly expressed in immature cells of the myelomonocytic lineage and in a subset of CD11b (Mac-1)-positive cells in some tissues. As with previously cloned Siglec-3-related mSiglecs, the lack of strong sequence similarity to a singular hSiglec made identification of the human ortholog difficult. We therefore conducted a comprehensive comparison of Siglecs between the human and mouse genomes. The mouse genome contains eight Siglec genes, whereas the human genome contains 11 Siglec genes and a Siglec-like gene. Although a one-to-one orthologous correspondence between human and mouse Siglecs 1, 2, and 4 is confirmed, the Siglec-3-related Siglecs showed marked differences between human and mouse. We found only four Siglec genes and two pseudogenes in the mouse chromosome 7 region syntenic to the Siglec-3-related gene cluster on human chromosome 19, which, in contrast, contains seven Siglec genes, a Siglec-like gene, and thirteen pseudogenes. Although analysis of gene maps and exon structures allows tentative assignments of mouse-human Siglec ortholog pairs, the possibility of unequal genetic recombination makes the assignments inconclusive. We therefore support a temporary lettered nomenclature for additional mouse Siglecs. Current information suggests that mSiglec-F is likely a hSiglec-5 ortholog. The previously reported mSiglec-3/CD33 and mSiglec-E/MIS are likely orthologs of hSiglec-3 and hSiglec-9, respectively. The other Siglec-3-like gene in the cluster (mSiglec-G) is probably a hSiglec-10 ortholog. Another mouse gene (mSiglec-H), without an apparent human ortholog, lies outside of the cluster. Thus, although some duplications of Siglec-3-related genes predated separation of the primate and rodent lineages (about 80 -100 million years ago), this gene cluster underwent extensive duplications in the primate lineage thereafter.Siglecs 1 (sialic acid-binding immunoglobulin superfamily lectins) are a family of cell surface proteins defined by certain shared structural motifs in the first two Ig-like domains and by their ability to recognize sialic acids via the first Ig V-set domain (1-4). Each Siglec has a distinct expression pattern (3, 4), suggesting that these molecules play unique roles in the cells expressing them. In humans, ten canonical Siglecs (3-5) and one Siglec-like molecule (6, 7) have been reported so far, and our analysis of human genome sequences suggests that there is only one additional Siglec.

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Section: Cloning Of a Novel Msiglec Cdna-a Partial Mouse Estsupporting

confidence: 70%

Cloning and Characterization of a Novel Mouse Siglec, mSiglec-F

Angata¹,

Hingorani²,

Varki³

et al. 2001

Journal of Biological Chemistry

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“…To explore whether Sn is directly involved in inducing cell death, CHO cells expressing Sn, a mutant form of Sn (SnR97A), and WT CHO were used (20). SnR97A lacks sugarbinding properties due to the substitution of arginine 97 with alanine (21). The viability of CD4 + T cells was significantly lower in cocultures with Sn CHO cells as compared with SnR97A and WT CHO groups.…”

Section: Engaging Snl On Cd4 + T Cells Induces Cell Deathmentioning

confidence: 99%

Sialoadhesin Ligand Expression Identifies a Subset of CD4+Foxp3− T Cells with a Distinct Activation and Glycosylation Profile

Kidder

Richards

Ziltener³

et al. 2013

The Journal of Immunology

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Sialoadhesin (Sn) is a sialic acid–binding Ig-like lectin expressed selectively on macrophage subsets. In a model of experimental autoimmune encephalomyelitis, Sn interacted with sialylated ligands expressed selectively on CD4+Foxp3+ regulatory T cells (Tregs) and inhibited their proliferation. In this study, we examined the induction of Sn ligands (SnL) on all splenic CD4+ T cells following in vitro activation. Most CD4+ Tregs strongly upregulated SnL, whereas only a small subset of ∼20% CD4+Foxp3− T cells (effector T cells [Teffs]) upregulated SnL. SnL+ Teffs displayed higher levels of activation markers CD25 and CD69, exhibited increased proliferation, and produced higher amounts of IL-2 and IFN-γ than corresponding SnL− Teffs. Coculture of activated Teffs with Sn+ macrophages or Sn+ Chinese hamster ovary cells resulted in increased cell death, suggesting a regulatory role for Sn–SnL interactions. The key importance of α2,3-sialylation in SnL expression was demonstrated by increased binding of α2,3-linkage–specific Maackia amurensis lectin, increased expression of α2,3-sialyltransferase ST3GalVI, and loss of SnL following treatment with an α2,3-linkage–specific sialidase. The induction of SnL on activated CD4+ T cells was dependent on N-glycan rather than O-glycan biosynthesis and independent of the mucin-like molecules CD43 and P-selectin glycoprotein ligand-1, previously implicated in Sn interactions. Induction of ligands on CD4+Foxp3− Teffs was also observed in vivo using the New Zealand Black × New Zealand White F1 murine model of spontaneous lupus and SnL levels on Teffs correlated strongly with the degree of proteinuria. Collectively, these data indicate that SnL is a novel marker of activated CD4+ Teffs that are implicated in the pathogenesis of autoimmune diseases.

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“…The polyclonal Ab was labeled with FITC or biotin following protocols recommended by the suppliers and titered by staining mouse bone marrow cells followed by FCM. The specificity of the Ab was determined by ELISA as described previously [31], using a panel of mouse Siglec-Fc fusion proteins as controls.…”

Section: Preparation Of Polyclonal Sheep Anti-msiglec-e Abmentioning

confidence: 99%

The murine inhibitory receptor mSiglec‐E is expressed broadly on cells of the innate immune system whereas mSiglec‐F is restricted to eosinophils

et al. 2004

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Murine (m) Siglec-E and mSiglec-F are recently discovered murine sialic acid-binding Ig-like lectins with tyrosine-based inhibitory signaling motifs. They are postulated to be the orthologs of human (h) siglec-7, -8 or -9 and siglec-5, respectively. We report here the first detailed characterization of mSiglec-E, and compare its expression pattern with mSiglec-F. Similar to hSiglec-7, mSiglec-E preferred § 2-8-linked disialic acid over § 2-3-and § 2-6-linked sialic acids. Using a specific Ab, FACS analysis demonstrated that mSiglec-E was expressed mainly on neutrophils in blood and their immature precursors in bone marrow. mSiglec-E was present on peritoneal cavity macrophages and on subsets of mature NK cells and splenic dendritic cells. mSiglec-E was also found on a novel population of peritoneal cavity B-1a-like cells and a subset of splenic B cells enriched in transitional T2 and marginal zone B cells. In striking contrast to mSiglec-E, mSiglec-F was expressed predominantly on eosinophils in blood and their precursors in the bone marrow. The distinct and largely nonoverlapping expression profiles of mSiglec-E and mSiglec-F suggest that they play nonredundant roles in the innate immune system. mSiglec-E is likely to modulate the functions of several types of effector cells, whereas mSiglec-F is likely to be more restricted to eosinophil biology.

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Characterization of the Sialic Acid-binding Site in Sialoadhesin by Site-directed Mutagenesis

Cited by 135 publications

References 49 publications

Cloning and Characterization of a Novel Mouse Siglec, mSiglec-F

Cloning and Characterization of a Novel Mouse Siglec, mSiglec-F

Sialoadhesin Ligand Expression Identifies a Subset of CD4+Foxp3− T Cells with a Distinct Activation and Glycosylation Profile

The murine inhibitory receptor mSiglec‐E is expressed broadly on cells of the innate immune system whereas mSiglec‐F is restricted to eosinophils

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