Abstract
The MHC class I binding proteins leukocyte immunoglobulin-like receptor (LIR)-1 and -2 recognize a similar broad spectrum of HLA-A, -B and -C alleles but are differentially expressed in lymphocytes, monocytes, and dendritic cells. In monocytes, phosphorylation of LIR-1 and LIR-2 results in the binding of the tyrosine phosphatase SHP-1. Coligation of either LIR with Fcgamma receptor I (CD64) inhibits tyrosine phosphorylation of the associated Fc receptor gamma chain and Syk molecules, as well as intracellular calcium mobilization. These findings suggest that LIR-1 and LIR-2 function as unique MHC class I receptors involved in the inhibition or down-modulation of monocyte activation signals, particularly those mediated through the receptors for IgG, IgE and IgA.
MeSH terms
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Alleles
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Animals
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Antigens, CD*
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Calcium / metabolism
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HLA Antigens / genetics
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Humans
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Intracellular Signaling Peptides and Proteins
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Leukocyte Immunoglobulin-like Receptor B1
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Monocytes / physiology*
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Phosphorylation
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases / physiology
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Protein-Tyrosine Kinases / physiology
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Rabbits
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Receptors, Fc / physiology*
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Receptors, Immunologic / physiology*
Substances
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Antigens, CD
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HLA Antigens
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Intracellular Signaling Peptides and Proteins
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LILRB1 protein, human
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Leukocyte Immunoglobulin-like Receptor B1
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Receptors, Fc
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Receptors, Immunologic
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Protein-Tyrosine Kinases
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PTPN11 protein, human
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PTPN6 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatase, Non-Receptor Type 6
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Protein Tyrosine Phosphatases
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Calcium