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Monoclonal Antibody Circadian Rhythm

$111
20 µl
$260
100 µl
APPLICATIONS
REACTIVITY
All Species Expected

Application Methods: Immunohistochemistry (Paraffin), Western Blotting

Background: Ubiquitin is a conserved polypeptide unit that plays an important role in the ubiquitin-proteasome pathway. Ubiquitin can be covalently linked to many cellular proteins by the ubiquitination process, which targets proteins for degradation by the 26S proteasome. Three components are involved in the target protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (1-3). The ubiquitin-proteasome pathway has been implicated in a wide range of normal biological processes and in disease-related abnormalities. Several proteins such as IκB, p53, cdc25A, and Bcl-2 have been shown to be targets for the ubiquitin-proteasome process as part of regulation of cell cycle progression, differentiation, cell stress response, and apoptosis (4-7).

$305
100 µl
This Cell Signaling Technology antibody is conjugated to the carbohydrate groups of horseradish peroxidase (HRP) via its amine groups. The HRP conjugated antibody is expected to exhibit the same species cross-reactivity as the unconjugated Ubiquitin (P4D1) Mouse mAb #3936.
APPLICATIONS
REACTIVITY
All Species Expected

Application Methods: Western Blotting

Background: Ubiquitin is a conserved polypeptide unit that plays an important role in the ubiquitin-proteasome pathway. Ubiquitin can be covalently linked to many cellular proteins by the ubiquitination process, which targets proteins for degradation by the 26S proteasome. Three components are involved in the target protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (1-3). The ubiquitin-proteasome pathway has been implicated in a wide range of normal biological processes and in disease-related abnormalities. Several proteins such as IκB, p53, cdc25A, and Bcl-2 have been shown to be targets for the ubiquitin-proteasome process as part of regulation of cell cycle progression, differentiation, cell stress response, and apoptosis (4-7).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Western Blotting

Background: β-transducin repeat-containing protein (β-TrCP or FBW1A) is an F-box family protein characterized by the presence of the protein-protein mediating F-box domain first described in cyclin F. F-box proteins act as substrate adaptors that target proteins containing a specific phosphorylated sequence element, referred to as a phosphodegron, to the SCF E3 ubiquitin ligase complex for ubiquitination (1,2). β-TrCP targets many important proteins with diverse functions, such as p53, H-Ras, Smad4, IκBα, β-catenin, and the cell cycle checkpoint protein claspin, for ubiquitin-mediated degradation (3-5). Research studies have shown that inhibition of β-TrCP expression has a demonstrated benefit in the treatment of prostate cancer (6).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Chromatin IP, Immunoprecipitation, Western Blotting

Background: Reverse orientation c-erbA gene α (Rev-erbα, EAR-1, or NR1D1) is a widely expressed member of the orphan nuclear receptor family of proteins (1). Rev-erbα is highly expressed in adipose tissue, skeletal muscle, brain and liver, and regulates cellular proliferation and differentiation. Expression increases during differentiation in adipocytes and ectopic expression of Rev-erbα potentiates the adipocyte differentiation of 3T3-L1 cells (2). In addition, expression oscillates with circadian rhythm in liver cells and Rev-erbα regulates expression of BMAL1, ApoA-I and ApoC-III, all key regulators of circadian rhythm (3-7). Phosphorylation of Rev-erbα Ser55 and Ser59 by GSK-3β appears to stabilize Rev-erbα protein levels and is important for synchronizing and maintaining the circadian clock (8). Rev-erbα also regulates inflammation by targeting the NF-κB responsive genes IL-6 and COX-2 (9). Rev-erbα lacks the activation function 2 domain required for ligand-dependent activation of transcription by other members of the nuclear receptor family; thus it behaves as a constitutive repressor protein, recruiting the nuclear receptor co-repressor (N-CoR)/HDAC3 complex to target genes to repress transcription (10).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Western Blotting

Background: Ubiquitin is a conserved polypeptide unit that plays an important role in the ubiquitin-proteasome pathway. Ubiquitin can be covalently linked to many cellular proteins by the ubiquitination process, which targets proteins for degradation by the 26S proteasome. Three components are involved in the target protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (1-3). The ubiquitin-proteasome pathway has been implicated in a wide range of normal biological processes and in disease-related abnormalities. Several proteins such as IκB, p53, cdc25A, and Bcl-2 have been shown to be targets for the ubiquitin-proteasome process as part of regulation of cell cycle progression, differentiation, cell stress response, and apoptosis (4-7).

$303
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Flow Cytometry, Immunofluorescence (Immunocytochemistry)

Background: Ubiquitin is a conserved polypeptide unit that plays an important role in the ubiquitin-proteasome pathway. Ubiquitin can be covalently linked to many cellular proteins by the ubiquitination process, which targets proteins for degradation by the 26S proteasome. Three components are involved in the target protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (1-3). The ubiquitin-proteasome pathway has been implicated in a wide range of normal biological processes and in disease-related abnormalities. Several proteins such as IκB, p53, cdc25A, and Bcl-2 have been shown to be targets for the ubiquitin-proteasome process as part of regulation of cell cycle progression, differentiation, cell stress response, and apoptosis (4-7).

$303
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Immunoprecipitation, Western Blotting

Background: Ubiquitin is a conserved polypeptide unit that plays an important role in the ubiquitin-proteasome pathway. Ubiquitin can be covalently linked to many cellular proteins by the ubiquitination process, which targets proteins for degradation by the 26S proteasome. Three components are involved in the target protein-ubiquitin conjugation process. Ubiquitin is first activated by forming a thiolester complex with the activation component E1; the activated ubiquitin is subsequently transferred to the ubiquitin-carrier protein E2, then from E2 to ubiquitin ligase E3 for final delivery to the epsilon-NH2 of the target protein lysine residue (1-3). The ubiquitin-proteasome pathway has been implicated in a wide range of normal biological processes and in disease-related abnormalities. Several proteins such as IκB, p53, cdc25A, and Bcl-2 have been shown to be targets for the ubiquitin-proteasome process as part of regulation of cell cycle progression, differentiation, cell stress response, and apoptosis (4-7).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: β-transducin repeat-containing protein (β-TrCP or FBW1A) is an F-box family protein characterized by the presence of the protein-protein mediating F-box domain first described in cyclin F. F-box proteins act as substrate adaptors that target proteins containing a specific phosphorylated sequence element, referred to as a phosphodegron, to the SCF E3 ubiquitin ligase complex for ubiquitination (1,2). β-TrCP targets many important proteins with diverse functions, such as p53, H-Ras, Smad4, IκBα, β-catenin, and the cell cycle checkpoint protein claspin, for ubiquitin-mediated degradation (3-5). Research studies have shown that inhibition of β-TrCP expression has a demonstrated benefit in the treatment of prostate cancer (6).

$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: PPARγ coactivator-1α (PGC-1α) was originally identified as a transcriptional coactivator whose expression closely correlated with adaptive thermogenesis following exposure to cold temperatures (1). Named for its association with the nuclear receptor peroxisome-proliferator activated receptor (PPARγ), PGC-1α interacts with a diverse array of transcription factors to regulate numerous aspects of cell physiology (2). PGC-1α helps to regulate cell processes important in adaptive thermogenesis and energy metabolism, including the related functions of glucose uptake, gluconeogenesis, insulin secretion, and mitochondrial biogenesis (3). Long thought to be a potential therapeutic target for the treatment of type II diabetes, obesity, cardiomyopathy, or other metabolic disorders (reviewed in 4), a recent functional survey found no obvious differences in PPARγ activity associated with recognized PGC-1α variants (5).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse

Application Methods: Immunoprecipitation, Western Blotting

Background: Circadian rhythms govern many key physiological processes that fluctuate with a period of approximately 24 hours. These processes include the sleep-wake cycle, glucose, lipid and drug metabolism, heart rate, hormone secretion, renal blood flow, and body temperature, as well as basic cellular processes such as DNA repair and the timing of the cell division cycle (1,2). The mammalian circadian system consists of many individual tissue-specific clocks (peripheral clocks) that are controlled by a master circadian pacemaker residing in the suprachiasmatic nuclei (SCN) of the brain (1,2). The periodic circadian rhythm is prominently manifested by the light-dark cycle, which is sensed by the visual system and processed by the SCN. The SCN processes the light-dark information and synchronizes peripheral clocks through neural and humoral output signals (1,2).The cellular circadian clockwork consists of interwoven positive and negative regulatory loops, or limbs (1,2). The positive limb includes the CLOCK and BMAL1 proteins, two basic helix-loop-helix-PAS containing transcription factors that bind E box enhancer elements and activate transcription of their target genes. CLOCK is a histone acetyltransferase (HAT) protein, which acetylates both histone H3 and H4 (3). BMAL1 binds to CLOCK and enhances its HAT activity (3). The CLOCK/BMAL1 dimer exhibits a periodic oscillation in both nuclear/cytoplasmic localization and protein levels, both of which are regulated by phosphorylation (4,5). CLOCK/BMAL1 target genes include the Cry and Per genes, whose proteins form the negative limb of the circadian clockwork system (1,2). CRY and PER proteins (CRY1, CRY2, PER1, PER2 and PER3) form oligomers that also periodically shuttle between the nucleus and cytoplasm. When in the nucleus, CRY/PER proteins inhibit CLOCK/BMAL1-mediated transcriptional activation, thus completing the circadian transcriptional loop (1,2). In tissues, roughly six to eight percent of all genes exhibit a circadian expression pattern (1,2). This 24-hour periodicity in gene expression results from coordination of the positive and negative regulatory limbs of the cellular clockwork system, and is fine-tuned by outside signals received from the SCN.

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Chromatin IP, Immunoprecipitation, Western Blotting

Background: Circadian rhythms govern many key physiological processes that fluctuate with a period of approximately 24 hours. These processes include the sleep-wake cycle, glucose, lipid and drug metabolism, heart rate, hormone secretion, renal blood flow, and body temperature, as well as basic cellular processes such as DNA repair and the timing of the cell division cycle (1,2). The mammalian circadian system consists of many individual tissue-specific clocks (peripheral clocks) that are controlled by a master circadian pacemaker residing in the suprachiasmatic nuclei (SCN) of the brain (1,2). The periodic circadian rhythm is prominently manifested by the light-dark cycle, which is sensed by the visual system and processed by the SCN. The SCN processes the light-dark information and synchronizes peripheral clocks through neural and humoral output signals (1,2).The cellular circadian clockwork consists of interwoven positive and negative regulatory loops, or limbs (1,2). The positive limb includes the CLOCK and BMAL1 proteins, two basic helix-loop-helix-PAS containing transcription factors that bind E box enhancer elements and activate transcription of their target genes. CLOCK is a histone acetyltransferase (HAT) protein, which acetylates both histone H3 and H4 (3). BMAL1 binds to CLOCK and enhances its HAT activity (3). The CLOCK/BMAL1 dimer exhibits a periodic oscillation in both nuclear/cytoplasmic localization and protein levels, both of which are regulated by phosphorylation (4,5). CLOCK/BMAL1 target genes include the Cry and Per genes, whose proteins form the negative limb of the circadian clockwork system (1,2). CRY and PER proteins (CRY1, CRY2, PER1, PER2 and PER3) form oligomers that also periodically shuttle between the nucleus and cytoplasm. When in the nucleus, CRY/PER proteins inhibit CLOCK/BMAL1-mediated transcriptional activation, thus completing the circadian transcriptional loop (1,2). In tissues, roughly six to eight percent of all genes exhibit a circadian expression pattern (1,2). This 24-hour periodicity in gene expression results from coordination of the positive and negative regulatory limbs of the cellular clockwork system, and is fine-tuned by outside signals received from the SCN.

$305
100 µl
This Cell Signaling Technology antibody is conjugated to biotin under optimal conditions. The biotinylated antibody is expected to exhibit the same species cross-reactivity as the unconjugated Trk (pan) (A7H6R) Rabbit mAb #92991.
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Western Blotting

Background: The family of Trk receptor tyrosine kinases consists of TrkA, TrkB, and TrkC. While the sequence of these family members is highly conserved, they are activated by different neurotrophins: TrkA by NGF, TrkB by BDNF or NT4, and TrkC by NT3 (1). Neurotrophin signaling through these receptors regulates a number of physiological processes, such as cell survival, proliferation, neural development, and axon and dendrite growth and patterning (1). In the adult nervous system, the Trk receptors regulate synaptic strength and plasticity. TrkA regulates proliferation and is important for development and maturation of the nervous system (2). Phosphorylation at Tyr490 is required for Shc association and activation of the Ras-MAP kinase cascade (3,4). Residues Tyr674/675 lie within the catalytic domain, and phosphorylation at these sites reflects TrkA kinase activity (3-6). Point mutations, deletions, and chromosomal rearrangements (chimeras) cause ligand-independent receptor dimerization and activation of TrkA (7-10). TrkA is activated in many malignancies including breast, ovarian, prostate, and thyroid carcinomas (8-13). Research studies suggest that expression of TrkA in neuroblastomas may be a good prognostic marker as TrkA signals growth arrest and differentiation of cells originating from the neural crest (10).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: The family of Trk receptor tyrosine kinases consists of TrkA, TrkB, and TrkC. While the sequence of these family members is highly conserved, they are activated by different neurotrophins: TrkA by NGF, TrkB by BDNF or NT4, and TrkC by NT3 (1). Neurotrophin signaling through these receptors regulates a number of physiological processes, such as cell survival, proliferation, neural development, and axon and dendrite growth and patterning (1). In the adult nervous system, the Trk receptors regulate synaptic strength and plasticity. TrkA regulates proliferation and is important for development and maturation of the nervous system (2). Phosphorylation at Tyr490 is required for Shc association and activation of the Ras-MAP kinase cascade (3,4). Residues Tyr674/675 lie within the catalytic domain, and phosphorylation at these sites reflects TrkA kinase activity (3-6). Point mutations, deletions, and chromosomal rearrangements (chimeras) cause ligand-independent receptor dimerization and activation of TrkA (7-10). TrkA is activated in many malignancies including breast, ovarian, prostate, and thyroid carcinomas (8-13). Research studies suggest that expression of TrkA in neuroblastomas may be a good prognostic marker as TrkA signals growth arrest and differentiation of cells originating from the neural crest (10).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse

Application Methods: Immunoprecipitation, Western Blotting

Background: Inhibitor of DNA-binding-2 (Id2) is a member of the Id proteins which belong to the helix-loop-helix (HLH) protein family. The Id protein functions by binding to specific transcription factors and preventing their dimerization and DNA binding (1-3). Id2 interacts with a wide variety of transcription factors including E proteins (5), TCS (4), Pax (6) and the tumor suppressor Rb (1). Id2 has been shown to be important in regulating cellular differentiation, proliferation, development and tumorgenesis (7-9). In tumor cells, increased levels of Id2 functionally inactivate Rb, leading to cellular transformation and cancer (10,11). Id2 is therefore a promising therapeutic target for treatment of cancer (12).

$111
20 µl
$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Immunofluorescence (Immunocytochemistry), Immunoprecipitation, Western Blotting

Background: Acetylation of the histone tail causes chromatin to adopt an "open" conformation, allowing increased accessibility of transcription factors to DNA. The identification of histone acetyltransferases (HATs) and their large multiprotein complexes has yielded important insights into how these enzymes regulate transcription (1,2). HAT complexes interact with sequence-specific activator proteins to target specific genes. In addition to histones, HATs can acetylate nonhistone proteins, suggesting multiple roles for these enzymes (3). In contrast, histone deacetylation promotes a "closed" chromatin conformation and typically leads to repression of gene activity (4). Mammalian histone deacetylases can be divided into three classes on the basis of their similarity to various yeast deacetylases (5). Class I proteins (HDACs 1, 2, 3, and 8) are related to the yeast Rpd3-like proteins, those in class II (HDACs 4, 5, 6, 7, 9, and 10) are related to yeast Hda1-like proteins, and class III proteins are related to the yeast protein Sir2. Inhibitors of HDAC activity are now being explored as potential therapeutic cancer agents (6,7).

$260
100 µl
APPLICATIONS
REACTIVITY
Bovine, Human, Monkey

Application Methods: Western Blotting

Background: PAI-1 is a secreted protein that belongs to the serine proteinase inhibitor (serpin) superfamily. It inhibits urokinase and tissue plasminogen activators (uPA and tPA) and thus, reduces the conversion of inactive plasminogen to plasmin (1). PAI-1 regulates fibrinolysis and plays an important role in vessel patency and tissue remodeling. Secreted PAI-1 interacts with the extracellular matrix (ECM) component vitronectin, thereby modulating cell-ECM interactions (2,3). PAI-1 is expressed in a variety of tissues with higher expression in liver, vascular endothelial cells, platelets, macrophages, and adipose tissue (1). Increased levels of PAI-1 are associated with deep vein thrombosis (4). Defects in PAI-1 cause plasminogen activator inhibitor-1 deficiency (PAI-1D), which is characterized by increased bleeding after injury or surgery (5). Research studies have shown that high levels of PAI-1 are associated with obesity, aging, insulin resistance, and type 2 diabetes (6-8). PAI-1 is transcriptionally regulated by TGF-β and mediates TGF-β-induced inhibition of cell migration and invasion in cancer cells (9). Studies have shown PAI-1 to be also involved in fibrosis (10).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Chromatin IP, Chromatin IP-seq, Immunoprecipitation, Western Blotting

Background: Acetylation of the histone tail causes chromatin to adopt an "open" conformation, allowing increased accessibility of transcription factors to DNA. The identification of histone acetyltransferases (HATs) and their large multiprotein complexes has yielded important insights into how these enzymes regulate transcription (1,2). HAT complexes interact with sequence-specific activator proteins to target specific genes. In addition to histones, HATs can acetylate nonhistone proteins, suggesting multiple roles for these enzymes (3). In contrast, histone deacetylation promotes a "closed" chromatin conformation and typically leads to repression of gene activity (4). Mammalian histone deacetylases can be divided into three classes on the basis of their similarity to various yeast deacetylases (5). Class I proteins (HDACs 1, 2, 3, and 8) are related to the yeast Rpd3-like proteins, those in class II (HDACs 4, 5, 6, 7, 9, and 10) are related to yeast Hda1-like proteins, and class III proteins are related to the yeast protein Sir2. Inhibitors of HDAC activity are now being explored as potential therapeutic cancer agents (6,7).

$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Chromatin IP, Immunofluorescence (Immunocytochemistry), Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting

Background: The most well characterized nuclear receptor corepressors are SMRT (silencing mediator for retinoic acid and thyroid hormone receptors) and its close paralog NCoR1 (nuclear receptor corepressor) (1,2). NCoR1 functions to transcriptionally silence various unliganded, DNA bound non-steroidal nuclear receptors by serving as a large molecular scaffold that bridges the receptors with multiple chromatin remodeling factors that repress nuclear receptor-mediated gene transcription, in part, through deacetylation of core histones surrounding target promoters. Indeed, the N-terminal portion of NCoR1 possesses multiple distinct transcriptional repression domains (RDs) reponsible for the recruitment of additional components of the corepressor complex such as HDACs, mSin3, GPS2, and TBL1/TBLR1. In between the RDs lies a pair of potent repressor motifs known as SANT motifs (SWI3, ADA2, N-CoR, and TFIIIB), which recruit HDAC3 and histones to the repressor complex in order to enhance HDAC3 activity (3). The C-terminal portion of NCoR1 contains multiple nuclear receptor interaction domains (NDs), each of which contains a conserved CoRNR box (or L/I-X-X-I/V-I) motif that allow for binding to various unliganded nuclear hormone receptors such as thyroid hormone (THR) and retinoic acid (RAR) receptors (4,5).Recent genetic studies in mice have not only corroborated the wealth of biochemical studies involving NCoR1 but have also provided significant insight regarding the function of NCoR1 in mammalian development and physiology. Although it has been observed that loss of Ncor1 does not affect early embyonic development, likely due to compensation by Smrt, embryonic lethality ultimately results during mid-gestation, largely due to defects in erythropoesis and thymopoesis (6). Another study demonstrated that the NDs of NCoR1 are critical for its ability to function in a physiological setting as a transcriptional repressor of hepatic THR and Liver X Receptor (LXR) (7).

$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Immunoprecipitation, Western Blotting

Background: Carnitine palmitoyltransferase-1 (CPT1), localized to the mitochondrial outer membrane, translocates fatty acids across the mitochondrial membranes and catalyzes the rate-limiting step of β-oxidation (1, 2). There are three isoforms of this enzyme: CPT1A (liver), CPT1B (muscle), and CPT1C (brain) (1, 2). Deficiency of CPT1A results in an autosomal recessive mitochondrial fatty acid oxidation disorder (3). Studies have shown that physiological high blood glucose and insulin levels inhibit CPT1B activity in human muscle and therefore divert long-chain fatty acids toward storage in human muscle as triglycerides (4). Furthermore, mice deficient in CPT1C show less food intake and reduced body weight (5). These findings suggest that CPT1 may play a role in metabolic syndromes.

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse

Application Methods: Immunoprecipitation, Western Blotting

Background: CBP (CREB-binding protein) and p300 are highly conserved and functionally related transcriptional co-activators that associate with transcriptional regulators and signaling molecules, integrating multiple signal transduction pathways with the transcriptional machinery (1,2). CBP/p300 also contain histone acetyltransferase (HAT) activity, allowing them to acetylate histones and other proteins (2). Phosphorylation of p300 at Ser89 by PKC represses its transciptional acitivity, and phosphorylation at the same site by AMPK disrupts the association of p300 with nuclear receptors (3,4). Ser1834 phosphorylation of p300 by Akt disrupts its association with C/EBPβ (5). Growth factors induce phosphorylation of CBP at Ser437, which is required for CBP recruitment to the transcription complex (6). CaM kinase IV phosphorylates CBP at Ser302, which is required for CBP-dependent transcriptional activation in the CNS (7). The role of acetylation of CBP/p300 is of particular interest (2,8). Acetylation of p300 at Lys1499 has been demonstrated to enhance its HAT activity and affect a wide variety of signaling events (9).