Abstract
The adaptor SAP, mutated in X-linked lymphoproliferative disease, has critical roles in multiple immune cell types. Among these, SAP is essential for the ability of natural killer (NK) cells to eliminate abnormal hematopoietic cells. Herein, we elucidated the molecular and cellular bases of this activity. SAP enhanced NK cell responsiveness by a dual molecular mechanism. It coupled SLAM family receptors to the kinase Fyn, which triggered the exchange factor Vav-1 and augmented NK cell activation. SAP also prevented the inhibitory function of SLAM family receptors. This effect was Fyn independent and correlated with uncoupling of SLAM family receptors from the lipid phosphatase SHIP-1. Both mechanisms cooperated to enable conjugate formation with target cells and to stimulate cytotoxicity and cytokine secretion by NK cells. These data showed that SAP secures NK cell activation by a dichotomous molecular mechanism, which is required for conjugate formation. These findings may have implications for the role of SAP in other immune cell types.
Copyright © 2012 Elsevier Inc. All rights reserved.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, CD / immunology*
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Antigens, CD / metabolism
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Binding Sites
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CHO Cells
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Calcium Signaling / drug effects
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Cell Adhesion
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Cell Line, Tumor
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Cricetinae
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Cricetulus
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Cytotoxicity, Immunologic
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Egtazic Acid / analogs & derivatives
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Egtazic Acid / pharmacology
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Inositol Polyphosphate 5-Phosphatases
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Intracellular Signaling Peptides and Proteins / chemistry
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / physiology*
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Killer Cells, Lymphokine-Activated / enzymology
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Killer Cells, Lymphokine-Activated / immunology*
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Lymphocyte Activation / immunology*
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Lymphoma, T-Cell / pathology
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Melanoma, Experimental / pathology
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Mice
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Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
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Phospholipase C gamma / physiology
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Phosphoric Monoester Hydrolases / physiology*
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Protein Structure, Tertiary
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Proto-Oncogene Proteins c-fyn / physiology*
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Proto-Oncogene Proteins c-vav / physiology*
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Receptors, Cell Surface / immunology*
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Receptors, Cell Surface / metabolism
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Signaling Lymphocytic Activation Molecule Associated Protein
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Signaling Lymphocytic Activation Molecule Family Member 1
Substances
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Antigens, CD
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Intracellular Signaling Peptides and Proteins
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Proto-Oncogene Proteins c-vav
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Receptors, Cell Surface
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Sh2d1a protein, mouse
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Signaling Lymphocytic Activation Molecule Associated Protein
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Vav1 protein, mouse
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1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester
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Signaling Lymphocytic Activation Molecule Family Member 1
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Egtazic Acid
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Fyn protein, mouse
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Proto-Oncogene Proteins c-fyn
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Phosphoric Monoester Hydrolases
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Inositol Polyphosphate 5-Phosphatases
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Inpp5d protein, mouse
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Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
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Phospholipase C gamma