Presentation on theme: "Histone Acetyl Transferases"— Presentation transcript:
1Histone Acetyl Transferases HATHistone Acetyl Transferases3 HAT FamiliesPiu’ importanti sono GCN5 e omologo di PCAFH3-H4 istoni piu acetilatiAcetilano anche altre proteine oltre istoni3 famiglie in base alla loro strutturaSolitamente correlate a attivazione genicaAttività anomale da parte degli enzimi HDACs sono state evidenziate in molti diversi tipi di cancro, come la leucemia promielocitica, la leucemia mielogena acuta, il linfoma di non-Hodgkin, e altri tipi di carcinomi colorettali e gastrici. Quando questi enzimi agiscono in modo "scorretto," possono impedire la trascrizione di geni fondamentali.
2KAT3 Family: p300 (E1Abinding protein) and CBP(CREB binding protein) Cbp e p300 sono identicheScoperta prima cbpInteragisce con gli attori principali del macchinario di trascrizione tra cui RNA pol2Dominio HAT responsabile della sua attivita’Principali domini della proteina permettono di interagire con diversi TFInfatti non lega direttamente il DNA ma fa da cofattore e attivatoreCreb binding domain, bromo domain (readers), glutamine rich domain attivazioneFAT factor acetyl transferase
3P300/CBP in cancerRubinstein–Taybi syndrome (RTS) is a developmental disorder caused by heterozygous germline mutations (point mutations, translocations or deletions) of the CBP gene. RTS is characterized by broad thumbs, cranio-facial and cardiac abnormalities, as well as mental retardation. Patients with RTS have an increased predisposition to cancerM4/M5 subtype of acute myeloid leukemia (AML) This translocation fuses the gene encoding the monocytic leukemia zinc- finger protein (MOZ) with the amino terminus of CBP. aberrant acetylationMLL-CBP and MLL-p300 translocations (MLL-mixed lineage leukemia) have alsobeen described.(AML) aberrant acetylation and methylationMutations in CBP or P300 are correlated with different type of tumorsChromosomal rearrangements involve CBP more commonly than p300.
4HDAC- Histone Deacetylase Classe1: omologo yRPD3 Deacetilano il gruppo acetileClassificati in base omologia con yeastClasse1: omologo yRPD3(dominio HDAC,nucleari)Classe2: omologo yHDA1(dominio HDAC, nucleari/citoplasmatiche(P))Classe 3: ySIRT2Classe 4:classificato per omologia di sequenza
5HDAC- Histone Deacetylase Classe 2a: residui forforilati conservati molto importanti per il shuttling tra nucleo e cytClasse 2b : ha due domini HDAC consecutiviSecondo gruppo sta nel cytoplasma (acetila proteine ) e fa shuttlingHDAC4This protein does not bind DNA directly, but throughtranscription factors MEF2C and MEF2DImportante nello sviluppo muscolareDopo differenziamento in miotubi hdac4 diventa nucleare quindi ha un ruolo attivo
6HDAC classe3 : SirIn general, sirtuins do not act autonomously but as components of large multiprotein complexes, such as pRb-E2F and mSin3A, that mediate important transcription regulatory pathways. Sirtuins have a role in regulation of transcription and apoptosis leading to substantial interest in inhibitors of these enzymes as possible antineoplastic agents. In addition, Sir2-like family deacteylases are involved in the normal ageing process through their role in resistance to cellular stress.Sirtuin-mediated deacetylation reaction couples lysine deacetylation to NAD hydrolysisSir2 family deacetylation target consensus sequences. The amino acid sequence of the Sir2 targets are shown: histone H3 lysine 9; histone H3 lysine 14; histone H4 lysine 16; p53 lysine 382;Tubulin, alba.
7PRMT and KMT: Methyl Transferases Attivazione o repressioneMLL importante nell leucemie infantiliInteragisce con : WDR5, RBBP5, MEN1 e ASH2L
8KMT: Lysin Methyl Transferases leukemiaKMT1 set domain preset post set domain1a 1 b contengono oltre al set domain un cromodomain1c e 1e un ankyrin domain fanno si di riconoscere histoni metilatiSegnale repressorioKMT2 family proteins are H3K4 methyltransferases, and they share a distinct SET domain with an essential post-SET region at the C-terminusThe H3K4 trimethylation activity of KDM2A requires compo- nents of its core complex, including WDR5, RbBP5, and Ash2LKMT3 histone H3K36, but their KMT activities are not restricted to H3K36 modifica nel corpo del geneKMT4 H3K79 methylation activity is essential for MLL-AF4 and MLL-AF9 fusion-induced leukemiastarget terapeuticoKMT5 segnale repressorio K20KMT6 Polycomb repressive complex2 repressioneNo Set domainPRC2
9KMT: SET domain ((Su(var)3-9, Enhancer of Zeste, Trithorax))
10PRMT:Protein arginine methyltransferases Domini altamente conservatiMotif I: VLD/EVGXGXG;Post I: V/IXG/AXD/E;Motif II: F/I/VDI/L/K;Double E LoopMotif III: LR/KXXG;THW loop
11PRMT Altamente omologa a RMT1 del lievito S-adenosilmetionina adenosilomocisteinaAltamente omologa a RMT1 del lievito
12KDM:Lysine Demethylase KDM1 non rimuove trimetil H3K4 e non solo ha altri substratiagiscono in un complesso CoREST and BHC80alter its substrates’ specificity toward H3K9 methylation when associated with nuclear receptors, thereby acting as a transcriptional coactivatorH3K9KDM2 first JmjC domain-containing histone demethylase identified . KDM2A and KDM2B demethylate mono- and di-methylation from H3K36, while KDM2B is also implicated in demethylation of H3K4The F-Box present in KDM2 family members suggests that KDM2 proteins might also be involved in additional mechanisms of chromatin regulation, such as ubiquitylationKDM3 funzionano come coattivatoriKDM4 Besides the JmjC domain, they share a highly conserved JmjN domain, and three of them (all except KDM4D) contain tandem PHD fingers and Tudor domains that read distinct histone methy- lation sono I primi che tolgono una trimetilazioneKdm5 KDM5 family members KDM5A – 5D/JARID1A – 1D specif- ically remove di- and tri-methylation from H3K4 [135 – 141]. They are multi domain-containing proteins characterized by a combination of JmjC and JmjN catalytic domains with an ARID DNA-binding domain, a C5HC2 zinc finger, and two to three PHD fingers. Distinct PHD fingers of KDM5A and KDM5C were shown to bind methylated H3K4 or H3K9, re- spectively. This family of proteins shows oncogen- ic activity, as KDM5A is overexpressed in gastric cancer and KDM5B is highly induced in breast cancerKDM6 H3K27-specific histone demethy- lases,KDM7 This family of proteins possesses strong demethylation activity toward H3K9 and H3K27 mono- and di-methylation [151–157]. Furthermore, PHF8 is able to remove mono-methylation from H4K20 [154,155,158]. All three KDM7 family proteins contain a PHD finger that binds to histone H3K4me3,
13KDMH3K9me3H3K4me3H3K27me3HnHanno in comune il JMJC domainAlcune hanno anche un Tudor domain che le rende in grado di riconoscee gli istoni metilatiH3K36me1,2
14 The Methylation of Histone Lysines Is Reversible and Regulates Gene Expression(A) Methylation of H3 K4 is often associated with active genes, and conversely, its demethylation accompanies gene repression.(B) In contrast, methylation of H3 K9 is often associated with silenced genes, hence removal of H3 K9 methyl marks coincides with gene activation.
15Figure 2. Regulation of LSD1 Specificity by Association with Protein Cofactors(Upper panel) Recombinant LSD1 specifically demethylates H3 K4 of core histones (A), but not H3 K9 (B) (Shi et al., 2004). (C) LSD1 demethylates H3 K9 when affinity purified in the presence of the androgen receptor (AR; Metzger et al., 2005).(Middle panel) (A) Recombinant LSD1 alone does not bind to or act upon nucleosomal substrates. (B) Association of LSD1 with CoREST endows LSD1 with the ability to demethylate H3 K4 on nucleosomal substrates (Lee et al., 2005; Shi et al., 2005). (C) BHC80 inhibits the demethylation of nucleosomes mediated by the LSD1-CoREST complex (Shi et al., 2005).(Lower panel) (A) LSD1, as part of the CoREST corepressor complex, is recruited to genes containing the REST-responsive repressor element 1 (RE1) and participates in gene silencing through demethylation of H3 K4 (Shi et al., 2004). (B) Ligand-induced recruitment of androgen receptor (AR) to the androgen receptor element (ARE) is accompanied by demethylation of H3 K9 by LSD1, leading to transcriptional activation (Metzger et al., 2005). However, LSD1 is already tethered to the ARE through an unknown mechanism (indicated by factor X) prior to the induction of gene expression by the androgen ligand.
23ASH2L: important for trymetilation of H3 K4 MEN1MEN1MEN1Molecular regulation of H3K4 trimethylation by ASH2L,a shared subunit of MLL complexesMelissa M Steward1, Jung-Shin Lee1, Aisling O’Donovan2,Matt Wyatt1,Bradley E Bernstein2 & Ali Shilatifard1,3SEPTEMBER 2006 NATURE STRUCTURAL & MOLECULAR BIOLOGY
36Global perturbations of histones PTMs in human cancers. H3K20me3 Lymphoma Fraga et al. Nat Genetmouse SCCH3K16ac (MOF) Lymphoma Fraga et al. Nat GenetBreast, Medulloblastoma Pfister ey al. Int J Cancer 2008.H3K4me2 (MLL) Prostate Seligson et al. NatureH3K18ac Prostate Seligson et al. NatureH3K9me2 Prostate, Kidney Seligson et al. Am J PatholEllinger et al. Prostate 2010.H3K18ac Lung, Kidney Seligson et al. Am J PatholEllinger et al. Prostate 2010.H3K27me3 (Pg) Prostate Yu et al. Caner Res