FRET analysis of protein tyrosine kinase c-Src activation mediated via aryl hydrocarbon receptor

AbstractThe aryl hydrocarbon receptor (AHR) is a cytosolic ligand-activated transcription factor involved in xenobiotic sensing, cell cycle regulation, and cell development. In humans, the activation of AHR by 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a high affinity AHR-ligand, impairs the secretion of immunoglobulin M (IgM) to suppress humoral immunity. However, the mechanisms bridging the activation of AHR and the impairment of IgM secretion by human primary B cells remain poorly understood. Recent transcriptomic analysis revealed upregulation of lymphocyte-specific protein tyrosine kinase (LCK) in AHR-activated human primary B cells. LCK is a well-characterized tyrosine kinase that phosphorylates critical signaling proteins involved in activation and cytokine production in T cells. Conversely, the role of LCK in human primary B cells is not well understood. In the current studies, we have verified the transcriptomic finding by detecting AHR-mediated upregulation of LCK protein in human primary B cells. We also confirmed the role of AHR in the upregulation of LCK by using a specific AHR antagonist, which abolished the AHR-mediated increase of LCK. Furthermore, we have confirmed the role of LCK in the AHR-mediated suppression of IgM by using LCK specific inhibitors, which restored the IgM secretion by human B cells in the presence of TCDD. Collectively, the current studies demonstrate a novel role of LCK in IgM response and provide new insights into the mechanism for AHR-mediated impairment of immunoglobulin secretion by human primary B cells.

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Platelet P-selectin expression: requirement for protein kinase C, but not protein tyrosine kinase or phosphoinositide 3-kinase

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613403 ◽

2003 ◽

Vol 89 (06) ◽

pp. 1016-1023 ◽

Cited By ~ 6

Author(s):

Danielle Libersan ◽

Yahye Merhi

Keyword(s):

Protein Kinase C ◽

Protein Kinase ◽

Tyrosine Kinase ◽

Protein Tyrosine Kinase ◽

Human Platelet ◽

The Novel ◽

Protein Tyrosine ◽

Kinase C ◽

Activated Platelets ◽

Phosphoinositide 3 Kinase

SummaryP-selectin is translocated from the α-granules to the surface of activated platelets where it participates in thrombosis and inflammation. We investigated the signaling pathways involved in thrombin-induced human platelet P-selectin expression. Assessed by flow cytometry, inhibition of protein kinase C (PKC) with chelerythrine reduced P-selectin expression by 66%, platelet/neutrophil binding, GPIIb/IIIa activation and aggregation (p<0.05). Gö 6976, an inhibitor of the conventional PKCs (α and β), did not alter P-selectin expression. However, rottlerin inhibited by 50% its expression (p<0.05), but only at doses that interfere with the novel (є, η) and atypical (ζ) PKCs. Inhibition of protein tyrosine kinase (PTK) and phosphoinositide 3-kinase (PI3-K) did not significantly affect P-selectin expression. In conclusion, thrombin-induced P-selectin expression is PKC-sensitive, but PTK and PI3-K-insensitive. The novel є and η and atypical ζ, but not the conventional α and β and the novel θ PKCs, may be involved in this process.

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Chronological Changes of the Contractile Mechanism in Prolonged Vasospasm after Subarachnoid Hemorrhage: From Protein Kinase C to Protein Tyrosine Kinase

Neurosurgery ◽

10.1097/00006123-200212000-00018 ◽

2002 ◽

Vol 51 (6) ◽

pp. 1468-1476 ◽

Cited By ~ 16

Author(s):

Masayo Koide ◽

Shigeru Nishizawa ◽

Seiji Ohta ◽

Tetsuo Yokoyama ◽

Hiroki Namba

Keyword(s):

Protein Kinase C ◽

Subarachnoid Hemorrhage ◽

Protein Kinase ◽

Tyrosine Kinase ◽

Protein Tyrosine Kinase ◽

Protein Tyrosine ◽

Contractile Mechanism ◽

Kinase C

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Endothelin-1–Induced Interleukin-8 Production in Human Brain-Derived Endothelial Cells Is Mediated by the Protein Kinase C and Protein Tyrosine Kinase Pathways

Blood ◽

10.1182/blood.v94.4.1291.416k33_1291_1299 ◽

1999 ◽

Vol 94 (4) ◽

pp. 1291-1299 ◽

Cited By ~ 1

Author(s):

R. Zidovetzki ◽

P. Chen ◽

M. Chen ◽

F.M. Hofman

Keyword(s):

Signal Transduction ◽

Endothelial Cells ◽

Protein Kinase C ◽

Protein Kinase ◽

Tyrosine Kinase ◽

Protein Tyrosine Kinase ◽

Protein Tyrosine ◽

Kinase C ◽

Eta Receptor ◽

Specific Inhibitors

We have previously demonstrated that endothelin-1 (Et-1) induces human central nervous system-derived endothelial cells (CNS-EC) to produce and secrete the chemokine interleukin 8 (IL-8). In the present study, we use specific inhibitors and activators to elucidate the signal transduction pathways involved in this process. Et-1–induced IL-8 production was blocked by ETA receptor antagonist BQ610, but not by ETB receptor antagonist BQ788, demonstrating that CNS-EC activation is initiated by Et-1 binding to the ETA receptor. IL-8 mRNA expression is blocked by the protein kinase C inhibitor bisindolylmaleimide or protein tyrosine kinase inhibitors, genestein and geldanamycin, establishing the involvement of the protein kinase C and protein tyrosine kinase pathways in the activation process. The transcription factor, NF-κB, is involved in Et-1 activation as determined by specific inhibitors of translocation and direct analysis of DNA-binding proteins. Neither inhibition nor activation of cAMP-dependent protein kinase affected IL-8 production in the absence or presence of Et-1. Similarly, no effect was observed upon inhibition of protein phosphatases by okadaic acid. Thus, the signal transduction process induced by Et-1 in CNS-EC, leading to increased mRNA IL-8 expression, is initiated by Et-1 binding to ETA receptor followed by subsequent activation of protein kinase C, protein tyrosine kinase, and NF-κB. Because increased expression of Et-1 is associated with hypertension and stroke and IL-8 is likely to be involved in the accumulation of neutrophils causing tissue damage in ischemic/reperfusion injury, identification of the mechanism involved in the Et-1–induced increase in IL-8 production may have significant therapeutic value.

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