The Tyrosine Kinase Pyk-2/Raftk Regulates Natural Killer (Nk) Cell Cytotoxic Response, and Is Translocated and Activated upon Specific Target Cell Recognition and Killing

NK cells are capable of killing virus-infected or tumor cells and producing IFN-γ. Resting NK cells, however, have only minimal cytolytic activity and secrete a low level of IFN-γ. The cytokine IL-15 can promote the expression of effector functions by resting NK cells. In this study, we demonstrate that suppressor of cytokine signaling 2 (SOCS2) has a novel role in IL-15–primed human NK cell function. SOCS2 expression was upregulated in NK cells following stimulation with IL-15. During IL-15–mediated NK cell priming, SOCS2 interacted with phosphorylated proline-rich tyrosine kinase 2 (Pyk2) at tyrosine 402 (p-Pyk2Tyr402) and induced the proteasome-mediated degradation of p-Pyk2Tyr402 via ubiquitination. Knockdown of SOCS2 resulted in the accumulation of p-Pyk2Tyr402 and blocked NK cell effector functions. In addition, NK cell cytolytic activity and IFN-γ production were inhibited by overexpression of the wild-type of Pyk2 but not by the overexpression of tyrosine 402 mutant of Pyk2. These results suggest that SOCS2 regulates human NK cell effector functions via control of phosphorylated Pyk2 depending on IL-15 existence.

Section: Il-15-induced Socs2 Stimulates the Degradation Of Phosphorylsupporting

confidence: 92%

Suppressor of Cytokine Signaling 2 Regulates IL-15–Primed Human NK Cell Function via Control of Phosphorylated Pyk2

Lee

Yun

Piao

et al. 2010

“…As controls, the signaling molecule PYK-2, as well as the MTOC and talin (data not shown), were also localized at NK cell-target cell contact areas, as reported for activated NK cells ( Fig. 2A, see arrowheads) (28). LAT was homogeneously distributed on the plasma membrane, but a patch was observed at the central zone of NK cell-target cell contact, colocalizing with the 2B4 cluster ( Fig.…”

Section: The 2b4 and Sap Localized At The Contact Area Of Resting Nk supporting

confidence: 74%

Dynamic Redistribution of the Activating 2B4/SAP Complex at the Cytotoxic NK Cell Immune Synapse

Roda-Navarro

Mittelbrunn

Ortega

et al. 2004

Self Cite

The 2B4 molecule (CD244) has been described as a coreceptor in human NK cell activation. However, the behavior of 2B4 during the cytotoxic NK cell immune synapse (NK-IS) formation remains undetermined. In this study, we demonstrate the redistribution of 2B4 and the signaling adaptor molecule, signaling lymphocyte activation molecule-associated protein (SAP), to the cytotoxic NK-IS upon formation of conjugates between resting NK cells and EBV-infected 721.221 human cells. Confocal microscopy showed that 2B4 localized at the central supramolecular activation cluster, surrounded by a peripheral supramolecular activation cluster containing talin within NK cell and ICAM-1 on target cells. Videomicroscopy studies with 2B4-GFP-transfected NK cells revealed that 2B4 redistributed to cytotoxic NK-IS as soon as the cell contact occurred. Simultaneously, a SAP-GFP also clustered at the contact site, where it remained during the interaction period. The 2B4 molecular clusters remained bound to the target cell even after NK cell detachment. These results underscore the function of 2B4 as an adhesion molecule and suggest a relevant role in the initial binding, scanning of target cells, and formation of cytotoxic NK-IS. Finally, these findings are indicative of an important role of the activating 2B4/signaling lymphocyte activation molecule-associated protein complex during the recognition of EBV-infected cells.

“…3, rows 1, 2, 5, 6, and 7) suggest that these signaling molecules might be translocated along with MTOC to the contact area with target cells during initiation of the cytolytic signaling cascade. The recent finding of PYK-2 association and cotranslocation with MTOC in cytolytic NK effector function supports this model for temporal and spatial regulation of cytotoxicity (28).…”

Section: Discussionsupporting

confidence: 52%

“…It has been shown that lipid rafts, enriched in signaling molecules, become polarized to the cell-cell contact area in NK cell conjugates with sensitive tumor cells, and this redistribution requires activation of Src and Syk kinases (27). It has also been shown that translocation of the MTOC is associated with activation of the tyrosine kinase, PYK-2 (28). In two other recent reports the inhibitory NK receptors and their corresponding MHC class I ligands were shown to colocalize in the contact area between NK cells and target cells (29,30).…”

mentioning

confidence: 99%

Spatial Organization of Signal Transduction Molecules in the NK Cell Immune Synapses During MHC Class I-Regulated Noncytolytic and Cytolytic Interactions

Vyas

Mehta

Morgan

et al. 2001

168

227

The cytolytic activity of NK cells is tightly regulated by inhibitory receptors specific for MHC class I Ags. We have investigated the composition of signal transduction molecules in the supramolecular activation clusters in the MHC class I-regulated cytolytic and noncytolytic NK cell immune synapses. KIR2DL3-positive NK clones that are specifically inhibited in their cytotoxicity by HLA-Cw*0304 and polyclonal human NK cells were used for conjugate formation with target cells that are either protected or are susceptible to NK cell-mediated cytotoxicity. Polarization of talin, microtubule-organizing center, and lysosomes occurred only during cytolytic interactions. The NK immune synapses were analyzed by three-dimensional immunofluorescence microscopy, which showed two distinctly different synaptic organizations in NK cells during cytolytic and noncytolytic interactions. The center of a cytolytic synapse with MHC class I-deficient target is comprised of a complex of signaling molecules including Src homology (SH)2-containing protein tyrosine phosphatase-1 (SHP-1). Closely related molecules with overlapping functions, such as the Syk kinases, SYK, and ZAP-70, and adaptor molecules, SH2 domain-containing leukocyte protein of 76 kDa and B cell linker protein, are expressed in activated NK cells and are all recruited to the center of the cytolytic synapse. In contrast, the noncytolytic synapse contains SHP-1, but is lacking other components of the central supramolecular activation cluster. These findings indicate a functional role for SHP-1 in both the cytolytic and noncytolytic interactions. We also demonstrate, in three-cell conjugates, that a single NK cell forms a cytolytic synapse with a susceptible target cell in the presence of both susceptible and nonsusceptible target cells.