1 / 17

Introduction

Introduction to AP-1. Introduction . Tumor necrosis factor- a (TNF a ) is a pro-inflammatory cytokine important in immune responses TNF a inhibits cAMP-stimulated Cyp17 transcription TNF a activates protein kinase C in Leydig cells

starbuck
Télécharger la présentation

Introduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to AP-1 Introduction • Tumor necrosis factor-a (TNFa) is a pro-inflammatory cytokine important in immune responses • TNFa inhibits cAMP-stimulated Cyp17 transcription • TNFa activates protein kinase C in Leydig cells • TNFa action is known to involve AP-1 factors in other systems

  2. Objectives Component One: Status • To determine if activation of AP-1 is involved in cAMP and/or TNFa signal transduction in MA-10 cells • To determine if cAMP and/or TNFa activate c-Jun kinase in MA-10 cells

  3. Effect of TNFa and cAMP on FOS and cJUN protein expression FOS C-JUN 68kDa 43kDa cAMP TNFa - + + - - - + + - + + - - - + +

  4. Effect of cAMP and TNFa on 3TPluc activity Component Two: Background

  5. - + - - - - - + - - - - - + - - - - - + - + - - - - - + - - - - - + - - - - - + - + - - - - - + - - - - - + - - - - - + - + - - - - - + - - - - - + - - - - - + FOS c-jun junB junD cAMP and TNFa vs. DNA-protein interactions with canonical AP-1 ab control cAMP cA+TNF TNFa

  6. Super-shift with AP-1 antibodies vs. canonical AP-1 binding element AP-1 FOS c-junjunB junD - + - - - - - - - - - - + - - - - - - - - - - + - - + + - + - - - - + - + - + + - - - - - + - + + +

  7. c-Jun Kinase:Stress Activated Protein Kinase/cJun Nuclear Kinase (SAPK/JNK) SAPK/JNKStress Activated Protein Kinase/c-Jun Kinase • A serine/threonine kinase • Phosphorylates c-Jun in the amino-terminus • Modulates transactivational activity • MAP-kinase, distinct from Erk and P38 • Activity depends on dual phosphorylation by serine/threonine and tyrosine kinases

  8. TNFa and cAMP vs. cJUN kinase activity 44 42 hrs 0 .25 .5 1 2 6 12 24 .25 .5 1 2 6 12 24 TNFa cAMP

  9. Time course of cJUN kinase activation

  10. TNFa and cAMP vs. MAPK activity ERK hrs 0 .25 .5 1 2 6 12 24 .25 .5 1 2 6 12 24 TNFa cAMP

  11. Time course of MAP kinase activation

  12. c-Jun kinase transactivation assay

  13. Effect of cAMP and TNF on c-Jun transactivation activity

  14. Summary Overall Status • Cyclic-AMP alone, but not TNF alone, stimulates 3TPluc activity • TNF enhances cAMP-stimulated 3TPluc activity • TNF stimulates c-Jun kinase (JNK) activity • TNF increases transactivational activity of c-jun • Cyclic-AMP induces Fos, c-Jun, junB and junD nuclear binding activity

  15. Conclusions Conclusions • These studies suggest that TNFa effects are promoter specific. • TNF inhibits cAMP-induced Cyp17 transcription but stimulates cAMP-induced activation of canonical AP-1 target genes

  16. MAP-kinase signaling pathways mitogen Stress/cytokine ? RAS ? Rac/Cdc42 ? RAF MEKK1,+ MEKK4,+ MEK1,2 SEK/JNKK MKK3 ERK1,2 SAPK/JNK1,2 p38 Elk1, Rsk cJun, ATF2, Elk1 ATF2

  17. Back to cytokines

More Related