1. Academic Validation
  2. Phospholipase Cgamma2 is critical for Dectin-1-mediated Ca2+ flux and cytokine production in dendritic cells

Phospholipase Cgamma2 is critical for Dectin-1-mediated Ca2+ flux and cytokine production in dendritic cells

  • J Biol Chem. 2009 Mar 13;284(11):7038-46. doi: 10.1074/jbc.M806650200.
Shengli Xu 1 Jianxin Huo Koon-Guan Lee Tomohiro Kurosaki Kong-Peng Lam
Affiliations

Affiliation

  • 1 Laboratory of Immunology, Bioprocessing Technology Institute, Agency for Science, Technology and Research, Singapore 138668.
Abstract

Dectin-1 is a C-type lectin that recognizes beta-glucan in the cell walls of fungi and plays an important role in anti-fungal immunity. It signals via tyrosine kinase Syk and adaptor protein Card9 to activate NF-kappaB leading to proinflammatory cytokine production in dendritic cells (DCs). Other than this, not much else is known of the mechanism of Dectin-1 signaling. We demonstrate here that stimulation of DCs with zymosan triggers an intracellular Ca2+ flux that can be attenuated by a blocking anti-Dectin-1 antibody or by pre-treatment of cells with the Phospholipase C (PLC) gamma-inhibitor U73122, suggesting that Dectin-1 signals via a PLCgamma pathway to induce Ca2+ flux in DCs. Interestingly, treatment of DCs with particulate curdlan, which specifically engages Dectin-1, results in the phosphorylation of both PLCgamma1 and PLCgamma2. However, we show that PLCgamma2 is the critical Enzyme for Dectin-1 signaling in DCs. PLCgamma2-deficient DCs have drastic impairment of Ca2+ signaling and are defective in their secretion of interleukin 2 (IL-2), IL-6, IL-10, IL-12, IL-23, and tumor necrosis factor alpha. PLCgamma2-deficient DCs also exhibit impaired activation of ERK and JNK MAPKs and AP-1 and NFAT transcription factors in response to Dectin-1 stimulation. In addition, PLCgamma2-deficient DCs are also impaired in their activation of NF-kappaB upon Dectin-1 engagement due to defective assembly of the Card9-Bcl10-Malt1 complex and impaired IKKalpha/beta activation and IkappaBalpha degradation. Thus, our data indicate that Pattern Recognition Receptors such as Dectin-1 could elicit Ca2+ signaling and that PLCgamma2 is a critical player in the Dectin-1 signal transduction pathway.

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