Dataset Information

PI3K links NKG2D signaling to a CrkL pathway involved in natural killer cell adhesion, polarity, and granule secretion.

ABSTRACT: The NK cell-activating receptor NKG2D plays a critical role in the destruction of malignant cells, but many of the cell-signaling mechanisms governing NKG2D-mediated cellular cytotoxicity are unknown. We have identified an NKG2D-mediated signaling pathway that governs both conjugate formation and cytotoxic granule polarization. We demonstrate that an interaction between the regulatory subunit of PI3K, p85, and the adaptor protein CrkL is required for efficient NKG2D-mediated cellular cytotoxicity. We show decreased NK cell-target cell conjugate formation in NK cells treated with PI3K inhibitors or depleted of CrkL. Independent of adhesion, we find that microtubule organization center polarization toward target cells expressing the NKG2D ligand MICA or toward anti-NKG2D-coated beads is impaired in the absence of CrkL. Ab-stimulated granule release is also impaired in NK cells depleted of CrkL. Furthermore, our data indicate that the small Ras family GTPase Rap1 is activated downstream of NKG2D engagement in a PI3K- and CrkL-dependent manner and is required for conjugate formation, MTOC (microtubule organizing center) polarization, and NKG2D-dependent cellular cytotoxicity. Taken together, our data identify an NKG2D-activated signaling pathway that collectively orchestrates NK cell adhesion, cell polarization, and granule release.

SUBMITTER: Segovis CM

PROVIDER: S-EPMC2706535 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

PI3K links NKG2D signaling to a CrkL pathway involved in natural killer cell adhesion, polarity, and granule secretion.

Segovis Colin M CM Schoon Renee A RA Dick Christopher J CJ Nacusi Lucas P LP Leibson Paul J PJ Billadeau Daniel D DD

Journal of immunology (Baltimore, Md. : 1950) 20090601 11

The NK cell-activating receptor NKG2D plays a critical role in the destruction of malignant cells, but many of the cell-signaling mechanisms governing NKG2D-mediated cellular cytotoxicity are unknown. We have identified an NKG2D-mediated signaling pathway that governs both conjugate formation and cytotoxic granule polarization. We demonstrate that an interaction between the regulatory subunit of PI3K, p85, and the adaptor protein CrkL is required for efficient NKG2D-mediated cellular cytotoxicit ...[more]

PMID: 19454690

Similar Datasets

Project description:Heterozygous mutations in the NLRP3 gene in patients with cryopyrin associated periodic syndrome (CAPS) lead to hyper-responsive inflammasome function. CAPS is a systemic auto-inflammatory syndrome characterized by the activation of the innate immune system induced by elevated pro-inflammatory cytokines, but the involvement of selective innate immune cells in this process is not fully understood. Neutrophil secretion and the toxic components of their granules are mediators of inflammation associated with several human diseases and inflammatory conditions. Here, using the Nlrp3A350V inducible mouse model (MWS CreT) that recapitulates human patients with the A352V mutation in NLRP3 observed in the Muckle-Wells sub-phenotype of CAPS, we studied the relationship between hyper-activation of the inflammasome and neutrophil exocytosis. Using a flow cytometry approach, we show that Nlrp3A350V (MWS) neutrophils express normal basal levels of CD11b at the plasma membrane and that the upregulation of CD11b from secretory vesicles in response to several plasma membrane or endocytic agonist including the bacterial-derived mimetic peptide formyl-Leu-Met-Phe (fMLF) and the unmethylated oligonucleotide CpG is normal in MWS neutrophils. Significant but modest CD11b upregulation in MWS neutrophils compared to wild type was only observed in response to GM-CSF and CpG. The same pattern was observed for the secretion of matrix metalloproteinase-9 (MMP-9) from gelatinase granules in that MMP-9 secretion in MWS neutrophils was not different from that observed in wild-type neutrophils except when stimulated with GM-CSF and CpG. In contrast, azurophilic granule secretion, whose cargoes constitute the most toxic secretory and pro-inflammatory factors of the neutrophil, was markedly dysregulated in MWS neutrophils under both basal and stimulated conditions. This could not be attributed to paracrine effects of secretory cytokines because IL-1? secretion by neutrophils was undetectable under these experimental conditions. The increased azurophilic granule exocytosis in MWS neutrophils was attenuated by treatment with the neutrophil exocytosis inhibitor Nexinhib20. In agreement with a possible neutrophil contribution to systemic inflammation in CAPS, the levels of neutrophil secretory proteins were significantly elevated in the plasma from Nlrp3A350V mice. Altogether, our data indicates an azurophilic granule-selective dysregulation of neutrophil exocytosis in CAPS.

Dataset Information

PI3K links NKG2D signaling to a CrkL pathway involved in natural killer cell adhesion, polarity, and granule secretion.

Publications

PI3K links NKG2D signaling to a CrkL pathway involved in natural killer cell adhesion, polarity, and granule secretion.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets