Phospholipase Cβ Is Critical for T Cell Chemotaxis

Abstract

Chemokines acting through G protein-coupled receptors play an essential role in the immune response. PI3K and phospholipase C (PLC) are distinct signaling molecules that have been proposed in the regulation of chemokine-mediated cell migration. Studies with knockout mice have demonstrated a critical role for PI3K in Gαi protein-coupled receptor-mediated neutrophil and lymphocyte chemotaxis. Although PLCβ is not essential for the chemotactic response of neutrophils, its role in lymphocyte migration has not been clearly defined. We compared the chemotactic response of peripheral T cells derived from wild-type mice with mice containing loss-of-function mutations in both of the two predominant lymphocyte PLCβ isoforms (PLCβ2 and PLCβ3), and demonstrate that loss of PLCβ2 and PLCβ3 significantly impaired T cell migration. Because second messengers generated by PLCβ lead to a rise in intracellular calcium and activation of PKC, we analyzed which of these responses was critical for the PLCβ-mediated chemotaxis. Intracellular calcium chelation decreased the chemotactic response of wild-type lymphocytes, but pharmacologic inhibition of several PKC isoforms had no effect. Furthermore, calcium efflux induced by stromal cell-derived factor-1α was undetectable in PLCβ2β3-null lymphocytes, suggesting that the migration defect is due to the impaired ability to increase intracellular calcium. This study demonstrates that, in contrast to neutrophils, phospholipid second messengers generated by PLCβ play a critical role in T lymphocyte chemotaxis.

Increased invasive behaviour in cutaneous squamous cell carcinoma with loss of basement-membrane type VII collagen

“…Increased expression of p-Smad2/3 in ColVII-null cells suggests activation of the Smad pathway, which is possibly linked to the CXCL10-CXCR3 pathway. CXCRs can act through PLC-β proteins to increase cell movement (Bach et al, 2007), which could explain the increase in PLC-β4 expression observed in ColVII-null SCC cells.…”

“…8A). Chemokine receptors (CXCRs) can generate lipidderived second messengers through PLC activation, leading to a rise in intracellular calcium and subsequent directional movement of cells (Bach et al, 2007). Expression of CXCL10, its receptor CXCR3, and PLC-β4 was examined in siCOL7 and siC cells by performing IF staining on sections of collagen:matrigel gels.…”

The regulation of cell motility and chemotaxis by phospholipid signaling

“…By contrast, PLC-␤ is clearly necessary for T-cell chemotaxis. It acts by transiently raising cytoplasmic Ca 2+ concentrations via inositol (1,4,5)-trisphosphate [Ins(1,4,5)P 3 , IP3] but does not influence PKC activity (Bach et al, 2007;Smit et al, 2003). The identities of the Ca 2+ -dependent downstream components (such as calmodulin kinases, myosin light-chain kinase or Rho kinase) that mediate the chemotactic response in Tcells remain elusive.…”

Evidence for Chemokine-mediated Coalescence of Preformed Flotillin Hetero-oligomers in Human T-cells

“…For F, transfected cells were incubated without or with latrunculin A, EGTA, U73343, or U73122 in the absence of SDF-1. FRET images were acquired on fixed cells using acceptor photobleaching as described in the legend of have been implicated in T-cell migration (15,16). In none of these studies has the role of calcium and PLC in T-cell polarization and flotillin capping been addressed.…”