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© The Rockefeller University Press,
0021-9525/2000//1249 $5.00
The Journal of Cell Biology, Volume 149, Number 6,
, 2000 1249-1262
Original Article |
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
fsanchez{at}hlpr.insalud.es
The compartmentalization of plasma membrane proteins has a key role in regulation of lymphocyte activation and development of immunity. We found that the proline-rich tyrosine kinase-2 (PYK-2/RAFTK) colocalized with the microtubule-organizing center (MTOC) at the trailing edge of migrating natural killer (NK) cells. When polyclonal NK cells bound to K562 targets, PYK-2 translocated to the area of NK–target cell interaction. The specificity of this process was assessed with NK cell clones bearing activatory or inhibitory forms of CD94/NKG2. The translocation of PYK-2, MTOC, and paxillin to the area of NK–target cell contact was regulated upon specific recognition of target cells through NK cell receptors, controlling target cell killing. Furthermore, parallel in vitro kinase assays showed that PYK-2 was activated in response to signals that specifically triggered its translocation and NK cell mediated cytotoxicity. The overexpression of both the wt and a dominant-negative mutant of PYK-2, but not ZAP-70 wt, prevented the specific translocation of the MTOC and paxillin, and blocked the cytotoxic response of NK cells. Our data indicate that subcellular compartmentalization of PYK-2 correlates with effective signal transduction. Furthermore, they also suggest an important role for PYK-2 on the assembly of the signaling complexes that regulate the cytotoxic response.
Key Words: CD94/NKG2 • cytotoxicity • microtubule-organizing center • cytoskeletal proteins • HLA-E
© 2000 The Rockefeller University Press
D. Sancho and M. Nieto contributed equally to this article.Dr. Nieto's current address is IGBMC, BP163, 67404 Illkirch Cédex, CU de Strasbourg, France.
Abbreviations used in this paper: EGFP, enhanced green fluorescent protein; FAK, Focal adhesion kinase; FN, fibronectin; HLA, human leukocyte antigen; IL-2, interleukin-2; ITIM, immunoreceptor tyrosine-based inhibitory motifs; MHC, molecular histocompatibility complex; MTOC, microtubule-organizing center; NK, natural killer; PYK-2, proline-rich tyrosine kinase 2; SHP, Src homology 2 domain containing protein tyrosine phosphatase.
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