Dynamic analysis of STAT6 signalling in living cells

• Published in: FEBS letters Vol. 532; no. 1; pp. 188 - 192
• Main Authors: Nelson, Glyn, Wilde, Geraint J.C, Spiller, David G, Sullivan, Elaine, Unitt, John F, White, Michael R.H
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 04.12.2002
• Subjects: Active Transport, Cell Nucleus; Cell Line; Cell Nucleus - metabolism; Confocal microscopy; EGFP, enhanced green fluorescent protein; Green fluorescent protein; Green Fluorescent Proteins; HeLa Cells; Humans; IL-4, interleukin 4; Interleukin-4 - pharmacology; JAK, janus kinase; Kinetics; Luminescent Proteins - genetics; Microscopy, Confocal; Microscopy, Fluorescence; NF-kappa B - metabolism; NF-κB; NF-κB, nuclear factor κB; Recombinant Fusion Proteins - analysis; Recombinant Fusion Proteins - metabolism; Signal Transduction; STAT6; STAT6 Transcription Factor; STAT6, signal transducer and activator of transcription protein 6; TNFα, tumour necrosis factor α; Trans-Activators - genetics; Trans-Activators - metabolism; Trans-Activators - physiology; Transcription Factor RelA; Transcriptional Activation; JAK, janus kinase; NF-κB; EGFP, enhanced green fluorescent protein; STAT6, signal transducer and activator of transcription protein 6; NF-κB, nuclear factor κB; Green fluorescent protein; Confocal microscopy; STAT6; TNFα, tumour necrosis factor α; IL-4, interleukin 4
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(02)03672-4

Functional activity of N- and C-terminal fluorescent fusion proteins between STAT6 and EGFP was demonstrated through IL-4-dependent transcriptional activation and nuclear translocation. The N-terminal (EGFP–STAT6) fusion protein appeared to be more active than the C-terminal fusion. In HEK-293 cells both fusion proteins formed fluorescent nuclear foci following IL-4 stimulation, but in HeLa cells nuclear accumulation was homogeneous. Stimulation of the NF-κB pathway through TNFα treatment, or expression of p65–EGFP fusion protein, repressed both basal STAT6-dependent transcriptional activity and the extent of activation in response to IL-4. This indicates a novel mechanism of inhibition of STAT6 signalling by NF-κB activation.