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Negative signaling pathways of the killer cell inhibitory receptor and Fc gamma RIIb1 require distinct phosphatases.

Gupta N, Scharenberg AM, Burshtyn DN, Wagtmann N, Lioubin MN, Rohrschneider LR, Kinet JP, Long EO - J. Exp. Med. (1997)

Bottom Line: When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition.In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal.These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, Rockville, Maryland 20852, USA.

ABSTRACT
Inhibition of natural killer (NK) cells by the killer cell inhibitory receptor (KIR) involves recruitment of the tyrosine phosphatase SHP-1 by KIR and is prevented by expression of a dominant negative SHP-1 mutant. Another inhibitory receptor, the low affinity Fc receptor for immunoglobulin G (IgG) (Fc gamma RIIb1), has been shown to bind SHP-1 when cocross-linked with the antigen receptor on B cells (BCR). However, coligation of Fc gamma RIIb1 with BCR and with Fc epsilon RI on mast cells leads to recruitment of the inositol 5' phosphatase SHIP and to inhibition of mast cells from SHP-1-deficient mice. In this study, we evaluated the ability of these two inhibitory receptors to block target cell lysis by NK cells, and the contribution of SHP-1 and SHIP to inhibition. Recombinant vaccinia viruses encoding chimeric receptors and dominant negative mutants of SHP-1 and SHIP were used for expression in mouse and human NK cells. When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition. A dominant negative mutant of SHP-1 reverted the inhibition mediated by the KIR cytoplasmic tail but not that mediated by Fc gamma RIIb1. In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal. These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

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Schematic representation of the chimeric receptors. Hybrid  molecules bearing the cytoplasmic tail of human FcγRIIb1 and the extracellular domains of KIR-cl6 or KIR-cl42 were generated as described.  Open, hatched, and shaded boxes represent sequences from KIR-6, KIR-42, and FcγRIIb1, respectively. Closed boxes represent transmembrane  regions and open bars in the cytoplasmic tails indicate the position of ITIMs.
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Figure 1: Schematic representation of the chimeric receptors. Hybrid molecules bearing the cytoplasmic tail of human FcγRIIb1 and the extracellular domains of KIR-cl6 or KIR-cl42 were generated as described. Open, hatched, and shaded boxes represent sequences from KIR-6, KIR-42, and FcγRIIb1, respectively. Closed boxes represent transmembrane regions and open bars in the cytoplasmic tails indicate the position of ITIMs.

Mentions: To test whether the cytoplasmic tail of FcγRIIb1 may inhibit NK cells, and to address the role of the tyrosine phosphatase SHP-1 and inositol phosphatase SHIP in the negative signal delivered by these receptors, chimeric molecules with the cytoplasmic tail of FcγRIIb1 and the extracellular domains of KIR-6 or KIR-42 were constructed (Fig. 1). As a control, a truncated version of KIR-6 was made (Fig. 1), which lacks both ITIM sequences that are essential for KIR-mediated inhibition (4, 15). KIR-6 prevents the lysis of HLA-Cw3 positive target cells, whereas KIR-42 prevents lysis of targets that express HLA-Cw4 (14). Recombinant vaccinia viruses were made that express the chimeric KIR-6/RIIb1, KIR-42/RIIb1, and KIR-6tr molecules.


Negative signaling pathways of the killer cell inhibitory receptor and Fc gamma RIIb1 require distinct phosphatases.

Gupta N, Scharenberg AM, Burshtyn DN, Wagtmann N, Lioubin MN, Rohrschneider LR, Kinet JP, Long EO - J. Exp. Med. (1997)

Schematic representation of the chimeric receptors. Hybrid  molecules bearing the cytoplasmic tail of human FcγRIIb1 and the extracellular domains of KIR-cl6 or KIR-cl42 were generated as described.  Open, hatched, and shaded boxes represent sequences from KIR-6, KIR-42, and FcγRIIb1, respectively. Closed boxes represent transmembrane  regions and open bars in the cytoplasmic tails indicate the position of ITIMs.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199004&req=5

Figure 1: Schematic representation of the chimeric receptors. Hybrid molecules bearing the cytoplasmic tail of human FcγRIIb1 and the extracellular domains of KIR-cl6 or KIR-cl42 were generated as described. Open, hatched, and shaded boxes represent sequences from KIR-6, KIR-42, and FcγRIIb1, respectively. Closed boxes represent transmembrane regions and open bars in the cytoplasmic tails indicate the position of ITIMs.
Mentions: To test whether the cytoplasmic tail of FcγRIIb1 may inhibit NK cells, and to address the role of the tyrosine phosphatase SHP-1 and inositol phosphatase SHIP in the negative signal delivered by these receptors, chimeric molecules with the cytoplasmic tail of FcγRIIb1 and the extracellular domains of KIR-6 or KIR-42 were constructed (Fig. 1). As a control, a truncated version of KIR-6 was made (Fig. 1), which lacks both ITIM sequences that are essential for KIR-mediated inhibition (4, 15). KIR-6 prevents the lysis of HLA-Cw3 positive target cells, whereas KIR-42 prevents lysis of targets that express HLA-Cw4 (14). Recombinant vaccinia viruses were made that express the chimeric KIR-6/RIIb1, KIR-42/RIIb1, and KIR-6tr molecules.

Bottom Line: When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition.In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal.These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, Rockville, Maryland 20852, USA.

ABSTRACT
Inhibition of natural killer (NK) cells by the killer cell inhibitory receptor (KIR) involves recruitment of the tyrosine phosphatase SHP-1 by KIR and is prevented by expression of a dominant negative SHP-1 mutant. Another inhibitory receptor, the low affinity Fc receptor for immunoglobulin G (IgG) (Fc gamma RIIb1), has been shown to bind SHP-1 when cocross-linked with the antigen receptor on B cells (BCR). However, coligation of Fc gamma RIIb1 with BCR and with Fc epsilon RI on mast cells leads to recruitment of the inositol 5' phosphatase SHIP and to inhibition of mast cells from SHP-1-deficient mice. In this study, we evaluated the ability of these two inhibitory receptors to block target cell lysis by NK cells, and the contribution of SHP-1 and SHIP to inhibition. Recombinant vaccinia viruses encoding chimeric receptors and dominant negative mutants of SHP-1 and SHIP were used for expression in mouse and human NK cells. When the KIR cytoplasmic tail was replaced by that of Fc gamma RIIb1, recognition of HLA class I on target cells by the extracellular domain resulted in inhibition. A dominant negative mutant of SHP-1 reverted the inhibition mediated by the KIR cytoplasmic tail but not that mediated by Fc gamma RIIb1. In contrast, a dominant negative mutant of SHIP reverted only the inhibition mediated by the Fc gamma RIIb1 tail, providing functional evidence that SHIP plays a role in the Fc gamma RIIb1-mediated negative signal. These data demonstrate that inhibition of NK cells by KIR involves primarily the tyrosine phosphatase SHP-1, whereas inhibition mediated by Fc gamma RIIb1 requires the inositol phosphatase SHIP.

Show MeSH
Related in: MedlinePlus