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http://purl.uniprot.org/citations/10428856http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/10428856http://www.w3.org/1999/02/22-rdf-syntax-ns#typehttp://purl.uniprot.org/core/Journal_Citation
http://purl.uniprot.org/citations/10428856http://www.w3.org/2000/01/rdf-schema#comment"We report the expression cloning of a novel leptin-binding protein of the immunoglobulin superfamily (OB-BP1) and a cross-hybridizing clone (OB-BP2) that is identical to a recently described sialic acid-binding I-type lectin called Siglec-5. Comparisons to other known Siglec family members (CD22, CD33, myelin-associated glycoprotein, and sialoadhesin) show that OB-BP1, OB-BP2/Siglec-5, and CD33/Siglec-3 constitute a unique related subgroup with a high level of overall amino acid identity: OB-BP1 versus Siglec-5 (59%), OB-BP1 versus CD33 (63%), and OB-BP2/Siglec-5 versus CD33 (56%). The cytoplasmic domains are not as highly conserved, but display novel motifs which are putative sites of tyrosine phosphorylation, including an immunoreceptor tyrosine kinase inhibitory motif and a motif found in SLAM and SLAM-like proteins. Human tissues showed high levels of OB-BP1 mRNA in placenta and moderate expression in spleen, peripheral blood leukocytes, and small intestine. OB-BP2/Siglec-5 mRNA was detected in peripheral blood leukocytes, lung, spleen, and placenta. A monoclonal antibody specific for OB-BP1 confirmed high expression in the cyto- and syncytiotrophoblasts of the placenta. Using this antibody on peripheral blood leukocytes showed an almost exclusive expression pattern on B cells. Recombinant forms of the extracellular domains of OB-BP1, OB-BP2/Siglec-5, and CD33/Siglec-3 were assayed for specific binding of leptin. While OB-BP1 exhibited tight binding (K(d) 91 nM), the other two showed weak binding with K(d) values in the 1-2 microM range. Studies with sialylated ligands indicated that OB-BP1 selectively bound Neu5Acalpha2-6GalNAcalpha (sialyl-Tn) allowing its formal designation as Siglec-6. The identification of OB-BP1/Siglec-6 as a Siglec family member, coupled with its restricted expression pattern, suggests that it may mediate cell-cell recognition events by interacting with sialylated glycoprotein ligands expressed on specific cell populations. We also propose a role for OB-BP1 in leptin physiology, as a molecular sink to regulate leptin serum levels."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.org/dc/terms/identifier"doi:10.1074/jbc.274.32.22729"xsd:string
http://purl.uniprot.org/citations/10428856http://purl.org/dc/terms/identifier"doi:10.1074/jbc.274.32.22729"xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Bazan J.F."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Bazan J.F."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Patel N."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Patel N."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Balasubramanian S."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Balasubramanian S."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Varki A."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Varki A."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Peterson D."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Peterson D."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Bell M.P."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Bell M.P."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Brinkman-Van der Linden E.C.M."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Brinkman-Van der Linden E.C.M."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Altmann S.W."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Altmann S.W."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Kastelein R.A."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Kastelein R.A."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Timans J.C."xsd:string
http://purl.uniprot.org/citations/10428856http://purl.uniprot.org/core/author"Timans J.C."xsd:string
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