The Co-activator-like Mediator Complex Forms a Molecular Bridge Between Activation Domains and Pol II Co-activator the general problem example of several upstream activators interacting with a single co-activator-like mediator complex Transcription Regulation And Gene Expression in Eukaryotes FS 2016 Graduate Course G2 P. Matthias and RG Clerc Pharmazentrum Hörsaal 2 16h15-18h00 REGULATORY MECHANISMS OF TRANSCRIPTION FACTOR FUNCTION •Protein synthesized •Protein phosphorylated •Ligand binding •Release inhibitor •Change partner, etc RG Clerc April 6. 2016 Transcription factors as final effectors of the cellular signaling cascade Regulatory Mechanisms of Transcription Factor Function Genes X. Lewin B. editor Regulatory Mechanisms of Transcription Factor Function CREB FOXO NFAT Genes X. Lewin B. editor Body plan is constructed through interactions of the developmentally regulated homeotic gene expression anterior early expression posterior late expression high RA response low RA response hindbrain trunk Alexander T and Krumlauf R. Ann.Rev.Cell.Dev.Biol: 25_431 (2009) Hoxb transcription factors mRNA distribution along the AP axis A staggered expression of the anterior border within somites is a property of the physical ordering along the chromosome: the colinearity Alexander T and Krumlauf R. Ann.Rev.Cell.Dev.Biol: 25_431 (2009) Transcription control of the Hox genes: insight into colinear activation P A p p p p a p a p a a a a Tarchini B and Duboule D. Dev.Cell 10_93 (2006) correlation between linear arrangement along the chromosome and spatial transcriptional regulation WT MUT WT MUT WT MUT Regulatory Mechanisms of Transcription Factor Function CREB FOXO NFAT Genes X. Lewin B. editor Activation of TRX following G-Protein Coupled Receptor GPCR Ligand Binding CREB (cyclic-AMP Responsive Elements Binding Protein) Structure of the CREB basic region/leucine zipper domain (amino acids 285–339) (bZIP) bound to the somatostatin CRE (TGACGTCA) Phosphorylation of CREB at Ser133 Induces Complex Formation With an α-Helical Domain in CBP KIX CBP-CREB complex Nuclear stress bodies are the main sites of accumulation of HSF1/2 in stressed cells The Heat Shock Transcription Factor DBD (wHTH) cgcctcGAAtgTTCgcGAAa -46 hsp70 The Heat Shock Factor Family Across Species Canonical HSE (multiple adjacent pentanucleotide motifs) cgcctcGAAtgTTCgcGAAa [-46 hsp70] Regulation of the HS Response and the HSF Cycle •Inert monomer in the cytoplasm and nucleus •Stress induced DNA binding and TA potential (hyperphosphorylation) •Trimerization •HSF binding protein (HSBP1) negatively regulates trimer •Dissociation of trimers •Generation of unactive monomers upon binding of chaperones Hsp70 and Hdj-1 Regulatory Mechanisms of Transcription Factor Function CREB FOXO NFAT Genes X. Lewin B. editor The Nuclear Pore Complex is the Gateway That Regulates the Two-Way Traffic Between the Nucleus and the Rest of the Cell The Nuclear Pore Complex is the Gateway That Regulates the Two-Way Traffic Between the Nucleus and the Rest of the Cell Nucleocytoplasmic Trafficking: Nucleopore Complex and Karyopherins Regulation of FoxO by Nuclear Shuttling in Response to AKT Mediated Phosphorylation Winged-helix family of trx factors are involved in development, metabolism, cell differentiation Fox=Forkhead box (100AA) Phosporylation stimulates nuclear export (NES) and prevents nuclear import (NLS) Regulation of FoxO by Nuclear Shuttling in Response to AKT Mediated Phosphorylation The activity of FoxO is tightly regulated by post-translational modifications including phosphorylation, acetylation and ubiquitylation Multiple Levels of Control of NFAT Signaling TCR, IGF, EGF inhibition CsA induction IL2,IL3,IL4,GMCSF,TNF TAD Gwack Y. et al. Cell Calcium 42:145-156 Cooperative Binding of Two Unrelated Transcription Factors to Neighboring Sites Chen L. and Harrison SC. Nature 392:42-48 NF-AT (REL homology domain), AP-1 (Fos-Jun) cooperatively bind a composite DNA site (ARRE from IL-2 promoter) Regulatory Mechanisms of Transcription Factor Function CREB FOXO NFAT Genes X. Lewin B. editor Hormone Dependent Gene Activation by a Homodimeric or Heterodimeric Nuclear Hormone Receptor Conformational Change of the LBD of Two Related Nuclear Hormone Receptors Upon Ligand Binding Regulatory Mechanisms of Transcription Factor Function CREB FOXO NFAT Genes X. Lewin B. editor The NFκB Paradigm: Signal Induced Degradation of a Cytosolic Inhibitor Proteins Which Activates the TF Phosphorylation dependent release by inhibitor (eg. iκB-α) upon polyubiquitination - proteasomal mediated degradation Baltimore D. Nature Immunology 12: 683-686 (2011) The NFκB/REL Family and IκB Proteins NF-kappa B p50 homodimer bound to DNA Müller CW, Harrisson SG and Verdine GL. Nature 373:311-317 The NFκB Paradigm: Signal Induced Degradation of Cytosolic Inhibitor Proteins Which Activates the TF: 25 years on ! TRX factors such as NFκB are final effectors of various cellular signaling cascades Oeckinghaus A. Hayden M. Ghosh S (2011) Nature Immunology 12:695-708 The NFκB patent Regulatory Mechanisms of Transcription Factor Function CREB FOXO NFAT Genes X. Lewin B. editor Helix-Loop-Helix Domains E box TF 5’CANNTG3’ Structural Classes Helix-Loop-Helix Domains - the DBD is Separated by Nonhelical Loops from the Leu-Zipper Region (Coiled-Coil) T. Kadesch Cell Growth and Diff.4:49 (1993) bHLH Factors Activity is Modulated by Partner Exchange bHLH dimers in which both subunits have a basic region can bind DNA; a dimer in which a subunit lacks the basic region (eg Id) cannot bind the promoter regulatory element Regulatory Mechanisms of Transcription Factor Function CREB FOXO NFAT Genes X. Lewin B. editor Cholesterol and Triglyceride Synthesis Pathways Domain Structure of SREBP’s Membrane Bound TF (sterol regulatory element (SRE) binding protein - 5’PyCAPyNPyCAPy3’) Sterol Dependent Two-Steps Proteolytic Cleavage of TF The Sterol Response: Cleavage to Release the Active TF Brown M. Goldstein JL. Cell 89 (1997) The canonical Wnt–β-catenin pathway W. Birchmeier. Nature Reviews 8:387-398 (2008) LEF-1/TCF-1 5’ C Y76 C HELIX 3 BASIC C-TERM L6 T M10 M13 T HELIX 2 T G HELIX 1 E28 A A G C 3’ Looking Beyond … The Joy of Learning is as Indispensable in Study as Breathing is in Life Simone Weil.