20% off purchase of 3 or more products* | Learn More >>

Product listing: Gα(o) Antibody, UniProt ID P09471 #3975 to Histone H3 (K36M Mutant Specific) Antibody, UniProt ID P84243 #26218

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Western Blotting

Background: Heterotrimeric guanine nucleotide-binding proteins (G proteins) consist of α, β and γ subunits and mediate the effects of hormones, neurotransmitters, chemokines, and sensory stimuli. To date, over 20 known Gα subunits have been classified into four families, Gα(s), Gα(i/o), Gα(q) and Gα(12), based on structural and functional similarities (1,2). Phosphorylation of Tyr356 of Gα(q)/Gα(11) is essential for activation of the G protein, since phenylalanine substitution for Tyr356 changes the interaction of Gα with receptors and abolishes ligand-induced IP3 formation (3).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Western Blotting

Background: Heterotrimeric guanine nucleotide-binding proteins (G proteins) consist of α, β and γ subunits and mediate the effects of hormones, neurotransmitters, chemokines, and sensory stimuli. To date, over 20 known Gα subunits have been classified into four families, Gα(s), Gα(i/o), Gα(q) and Gα(12), based on structural and functional similarities (1,2). Phosphorylation of Tyr356 of Gα(q)/Gα(11) is essential for activation of the G protein, since phenylalanine substitution for Tyr356 changes the interaction of Gα with receptors and abolishes ligand-induced IP3 formation (3).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Immunohistochemistry (Paraffin), Western Blotting

Background: Cell growth is a fundamental biological process whereby cells accumulate mass and increase in size. The mammalian Target of Rapamycin (mTOR) pathway regulates growth by coordinating energy and nutrient signals with growth factor-derived signals (1). mTOR is a large protein kinase with two different complexes. One complex contains mTOR, GβL, and raptor, which is a target of rapamycin. The other complex, insensitive to rapamycin, includes mTOR, GβL, and rictor (1). GβL associates with the kinase domain of mTOR and stimulates mTOR kinase activity (2). A reduction in GβL expression has been shown to decrease in vivo phosphorylation of S6K1 (2).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that causes symptoms including hamartomas in brain, kidney, heart, lung and skin (1). The tumor suppressor genes TSC1 and TSC2 encode hamartin and tuberin, respectively (2,3). Hamartin and tuberin form a functional complex and are involved in numerous cellular activities such as vesicular trafficking, regulation of the G1 phase of the cell cycle, steroid hormone regulation, Rho activation and anchoring neuronal intermediate filaments to the actin cytoskeleton (4-9). The combination of genetic, biochemical and cell-biological studies demonstrate that the tuberin/hamartin complex functions as a GTPase-activating protein for the Ras-related small G protein Rheb and thus inhibits targets of rapamycin including mTOR. Cells lacking hamartin or tuberin fail to inhibit phosphorylation of S6 kinase resulting in the activation of S6 ribosomal protein's translation of 5'TOP mRNA transcripts (10). Hamartin is phosphorylated by CDK1 (cdc2) at Thr417, Ser584 and Thr1047 in cells in G2/M phase of the cell cycle (11).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Western Blotting

Background: Ubiquitinating enzymes (UBEs) catalyze protein ubiquitination, a reversible process countered by deubiquitinating enzyme (DUB) action (1,2). Five DUB subfamilies are recognized, including the USP, UCH, OTU, MJD and JAMM enzymes. Herpesvirus-associated ubiquitin-specific protease (HAUSP, USP7) is an important deubiquitinase belonging to USP subfamily. A key HAUSP function is to bind and deubiquitinate the p53 transcription factor and an associated regulator protein Mdm2, thereby stabilizing both proteins (3,4). In addition to regulating essential components of the p53 pathway, HAUSP also modifies other ubiquitinylated proteins such as members of the FoxO family of forkhead transcription factors and the mitotic stress checkpoint protein CHFR (5,6).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: Host cell factor C1 (HCFC1) was first identified as the host cell factor for human herpes simplex virus infection. HCFC1 and the viral protein VP16 belong to a multi-protein complex that promotes transcription of viral immediate early genes (1). The relatively large HCFC1 protein contains 6 centrally located 26 amino acid repeats that can be O-GlcNAcylated and subjected to O-linked beta-N-acetylglucosamine transferase (OGT) cleavage (2-4). The resulting amino-terminal (HCFC1-N) and carboxy-terminal (HCFC1-C) fragments are non-covalently associated and play important roles in cell cycle regulation. The HCFC1-N peptide facilitates progression through the G1 phase of the cell cycle while HCFC1-C enables proper mitosis and cytokinesis during the M phase (5-7). As HCFC1 plays an important role in neurodevelopment, mutations in the corresponding gene are associated with neurodevelopmental disorders (e.g., intellectual disability) in humans (8).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: Host cell factor C1 (HCFC1) was first identified as the host cell factor for human herpes simplex virus infection. HCFC1 and the viral protein VP16 belong to a multi-protein complex that promotes transcription of viral immediate early genes (1). The relatively large HCFC1 protein contains 6 centrally located 26 amino acid repeats that can be O-GlcNAcylated and subjected to O-linked beta-N-acetylglucosamine transferase (OGT) cleavage (2-4). The resulting amino-terminal (HCFC1-N) and carboxy-terminal (HCFC1-C) fragments are non-covalently associated and play important roles in cell cycle regulation. The HCFC1-N peptide facilitates progression through the G1 phase of the cell cycle while HCFC1-C enables proper mitosis and cytokinesis during the M phase (5-7). As HCFC1 plays an important role in neurodevelopment, mutations in the corresponding gene are associated with neurodevelopmental disorders (e.g., intellectual disability) in humans (8).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse

Application Methods: 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, Monkey, Mouse, Rat

Application Methods: Immunofluorescence (Immunocytochemistry), 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, Monkey, Mouse

Application Methods: Western Blotting

Background: HELLS, or LSH1, is a lymphoid-specific helicase thought to be involved in cellular proliferation and leukemogenesis (1,2). It is believed to be a chromatin remodeler and is required for DNMT1-mediated methylation maintenance and DNMT3A/DNMT3B-mediated de novo methylation. The role of HELLS in methylation maintenance was thought to be largely confined to repetitive DNA sequences, including major and minor satellite sequences, rather than single copy genes (3,4); recent evidence suggests a role in genome-wide cysteine methylation at non-repeat sequences (5). De novo methylation maintenance is associated with silencing of specific genes, some known to be involved in pluripotency and lineage commitment (6,7).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Western Blotting

Background: The ErbB2 (HER2) proto-oncogene encodes a 185 kDa transmembrane, receptor-like glycoprotein with intrinsic tyrosine kinase activity (1). While ErbB2 lacks an identified ligand, ErbB2 kinase activity can be activated in the absence of a ligand when overexpressed and through heteromeric associations with other ErbB family members (2). Amplification of the ErbB2 gene and overexpression of its product are detected in almost 40% of human breast cancers (3). Binding of the c-Cbl ubiquitin ligase to ErbB2 at Tyr1112 leads to ErbB2 poly-ubiquitination and enhances degradation of this kinase (4). ErbB2 is a key therapeutic target in the treatment of breast cancer and other carcinomas and targeting the regulation of ErbB2 degradation by the c-Cbl-regulated proteolytic pathway is one potential therapeutic strategy. Phosphorylation of the kinase domain residue Tyr877 of ErbB2 (homologous to Tyr416 of pp60c-Src) may be involved in regulating ErbB2 biological activity. The major autophosphorylation sites in ErbB2 are Tyr1248 and Tyr1221/1222; phosphorylation of these sites couples ErbB2 to the Ras-Raf-MAP kinase signal transduction pathway (1,5).

$260
100 µl
$630
300 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Immunohistochemistry (Paraffin), Western Blotting

Background: The ErbB2 (HER2) proto-oncogene encodes a 185 kDa transmembrane, receptor-like glycoprotein with intrinsic tyrosine kinase activity (1). While ErbB2 lacks an identified ligand, ErbB2 kinase activity can be activated in the absence of a ligand when overexpressed and through heteromeric associations with other ErbB family members (2). Amplification of the ErbB2 gene and overexpression of its product are detected in almost 40% of human breast cancers (3). Binding of the c-Cbl ubiquitin ligase to ErbB2 at Tyr1112 leads to ErbB2 poly-ubiquitination and enhances degradation of this kinase (4). ErbB2 is a key therapeutic target in the treatment of breast cancer and other carcinomas and targeting the regulation of ErbB2 degradation by the c-Cbl-regulated proteolytic pathway is one potential therapeutic strategy. Phosphorylation of the kinase domain residue Tyr877 of ErbB2 (homologous to Tyr416 of pp60c-Src) may be involved in regulating ErbB2 biological activity. The major autophosphorylation sites in ErbB2 are Tyr1248 and Tyr1221/1222; phosphorylation of these sites couples ErbB2 to the Ras-Raf-MAP kinase signal transduction pathway (1,5).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Western Blotting

Background: Heregulin (HRG), also called neuregulin (NRG1), neu differentiation factor (NDF) or glial growth factor-2 (GGF-2), is a soluble growth factor synthesized as a transmembrane precursor molecule. Metalloproteinases and other proteases catalyze the cleavage of its extracellular domain which is then released and functions as a ligand for ErbB3 and ErbB4 receptor tyrosine kinase. The signaling pathways of HRG-ErbB3/ErbB4 are involved in regulation of cell proliferation, differentiation, invasion, and survival of both normal and malignant tissues (1,2). Abnormality of HRG-ErbB signaling leads to development of a variety of human diseases.HRG family has four isoforms including HRG-1, -2, -3 and -4, which are derived from alternative exon splicing. Moreover, they showed various tissue expression and biological activities (3).

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

Application Methods: Western Blotting

Background: The homocysteine-responsive, ER-resident ubiquitin-like domain member 1 protein (HERPUD1) is an ER membrane protein and putative component of the ER-membrane-associated protein degradation (ERAD) pathway (1). HERPUD1 is a transmembrane protein with both amino- and carboxy-termini exposed to the cytoplasm. The amino-terminal HERPUD1 region contains an ubiquitin-like (UBL) domain (1). Increased expression of HERPUD1 protein following ER stress and its association with ERAD component proteins suggests that HERPUD1 may play an integral role in ERAD pathway function (1). Research studies demonstrate that HERPUD1 associates with components of the ERAD machinery, such as the E3 ubiquitin ligase HRD1, which enhances HRD1-mediated ubiquitination and proteasomal degradation of potentially toxic ERAD substrates (2-4). The HERPUD1 protein may act as a molecular adaptor for the recruitment of ERAD machinery and the amino-terminal UBL domain may important for this function (3,4). The loss of HERPUD1 expression renders cells more susceptible to ER stress and apoptosis (5,6).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Western Blotting

Background: Hexokinase catalyzes the conversion of glucose to glucose-6-phosphate, the first step in glycolysis. Four distinct mammalian hexokinase isoforms, designated as hexokinase I, II, III, and IV (glucokinase), have been identified. Hexokinases I, II, and III are associated with the outer mitochondrial membrane and are critical for maintaining an elevated rate of aerobic glycolysis in cancer cells (Warburg Effect) (1) in order to compensate for the increased energy demands associated with rapid cell growth and proliferation (2,3).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Western Blotting

Background: Hexokinase catalyzes the conversion of glucose to glucose-6-phosphate, the first step in glycolysis. Four distinct mammalian hexokinase isoforms, designated as hexokinase I, II, III, and IV (glucokinase), have been identified. Hexokinases I, II, and III are associated with the outer mitochondrial membrane and are critical for maintaining an elevated rate of aerobic glycolysis in cancer cells (Warburg Effect) (1) in order to compensate for the increased energy demands associated with rapid cell growth and proliferation (2,3).

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

Application Methods: Immunoprecipitation, Western Blotting

Background: HGK (MAP4K4 or mitogen-activated protein kinase kinase kinase kinase 4) is a serine/threonine kinase that belongs to the mammalian STE20/MAP4K kinase family involved in response to environmental stress and cytokines such as TNF-α (1-3). HGK specifically activates the c-Jun N-terminal kinase (JNK) signaling pathway and increases AP-1-mediated transcriptional activity in vivo (1). HGK is broadly expressed in many types of human cancer and cancer cell lines and plays an important role in cell transformation, invasiveness, adhesion and migration (4,5).

$260
100 µl
APPLICATIONS
REACTIVITY
Bovine, Human, Monkey

Application Methods: Immunoprecipitation, Western Blotting

Background: Hic-5 is a LIM domain family member orginally identified as a TGFbeta1 and hydrogen peroxide inducible gene, and is nearly identical to the androgen receptor co-activator ARA55 (1-3). Hic-5 is structurally related to paxillin, and both proteins are localized to focal adhesions and thought to serve as adaptor molecules, linking signals from the extracellular matrix to cytoskeletal regulation and intracelluar signaling (4,5). Like paxillin, Hic-5 contains four LD motifs and four LIM domains. Expression of Hic-5 can affect cell growth and differentiation (6-8). Increased expression of Hic-5 is observed during cellular senescence in fibroblasts, and ectopic expression in immortalized fibroblasts suppressed cell growth (8). Unlike paxillin, Hic-5 may translocate to the nucleus in response to oxidants like hydrogen peroxide (9). It has been proposed that Hic-5 serves to shuttle redox signaling from focal adhesions to the nucleus where it acts as a transcriptional co-activator for some transciption factors including, Sp1 and PPARgamma (7,9,10). Phosphorylation of Hic-5 at Tyr60 by CAKbeta and Fyn may activiate Hic-5 signaling by allowing binding to downstream SH2 domain containing proteins (11).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Western Blotting

Background: Hypoxia-inducible factor 1 (HIF1) is a heterodimeric transcription factor that plays a critical role in the cellular response to hypoxia (1). The HIF1 complex consists of two subunits, HIF-1α and HIF-1β, which are basic helix-loop-helix proteins of the PAS (Per, ARNT, Sim) family (2). HIF1 regulates the transcription of a broad range of genes that facilitate responses to the hypoxic environment, including genes regulating angiogenesis, erythropoiesis, cell cycle, metabolism, and apoptosis. The widely expressed HIF-1α is typically degraded rapidly in normoxic cells by the ubiquitin/proteasomal pathway. Under normoxic conditions, HIF-1α is proline hydroxylated leading to a conformational change that promotes binding to the von Hippel Lindau protein (VHL) E3 ligase complex; ubiquitination and proteasomal degradation follows (3,4). Both hypoxic conditions and chemical hydroxylase inhibitors (such as desferrioxamine and cobalt) inhibit HIF-1α degradation and lead to its stabilization. In addition, HIF-1α can be induced in an oxygen-independent manner by various cytokines through the PI3K-AKT-mTOR pathway (5-7).HIF-1β is also known as AhR nuclear translocator (ARNT) due to its ability to partner with the aryl hydrocarbon receptor (AhR) to form a heterodimeric transcription factor complex (8). Together with AhR, HIF-1β plays an important role in xenobiotics metabolism (8). In addition, a chromosomal translocation leading to a TEL-ARNT fusion protein is associated with acute myeloblastic leukemia (9). Studies also found that ARNT/HIF-1β expression levels decrease significantly in pancreatic islets from patients with type 2 diabetes, suggesting that HIF-1β plays an important role in pancreatic β-cell function (10).

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

Application Methods: Western Blotting

Background: Hip (HSP70-interacting protein), also known as ST13 (suppression of tumorigenicity protein 13), is one of several co-chaperones that regulate activities of the HSP70 chaperone family (1,2). The homo-oligomeric protein Hip cooperates with HSP70 in protein folding by stabilizing the ADP-bound state of HSP70. Hip directly binds to the ATPase domain of HSP70 when it is converted to the ADP-bound state by proteins of the HSP40 family (3). By collaborating with other positive co-factors such as HSP40 and Hop, or competing with negative co-factors such as Bag1, Hip may facilitate the chaperone function of HSP70 in protein folding and repair, and in controlling the activity of regulatory proteins such as steroid receptors and various regulators of proliferation or apoptosis (4-8).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Western Blotting

Background: Members of the homeodomain-interacting protein kinase (HIPK1-4) family of serine/threonine kinases regulate gene transcription with effects on cell proliferation, differentiation, and apoptosis (1-3). HIPK1-3 are nuclear proteins that were originally described as co-repressors for homeobox transcription factors (1). HIPK proteins can interact with and/or phosphorylate many transcriptional regulators (4).

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

Application Methods: Immunoprecipitation, Western Blotting

Background: Epitope tags are useful for the labeling and detection of proteins using immunoblotting, immunoprecipitation, and immunostaining techniques. Because of their small size, they are unlikely to affect the tagged protein’s biochemical properties.

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

Application Methods: 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, Monkey, Mouse, Rat

Application Methods: 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, Monkey, Mouse, Rat

Application Methods: 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, Monkey, Mouse, Rat, Zebrafish

Application Methods: Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting

Background: Modulation of chromatin structure plays an important role in the regulation of transcription in eukaryotes. The nucleosome, made up of DNA wound around eight core histone proteins (two each of H2A, H2B, H3, and H4), is the primary building block of chromatin (1). The amino-terminal tails of core histones undergo various post-translational modifications, including acetylation, phosphorylation, methylation, and ubiquitination (2-5). These modifications occur in response to various stimuli and have a direct effect on the accessibility of chromatin to transcription factors and, therefore, gene expression (6). In most species, histone H2B is primarily acetylated at Lys5, 12, 15, and 20 (4,7). Histone H3 is primarily acetylated at Lys9, 14, 18, 23, 27, and 56. Acetylation of H3 at Lys9 appears to have a dominant role in histone deposition and chromatin assembly in some organisms (2,3). Phosphorylation at Ser10, Ser28, and Thr11 of histone H3 is tightly correlated with chromosome condensation during both mitosis and meiosis (8-10). Phosphorylation at Thr3 of histone H3 is highly conserved among many species and is catalyzed by the kinase haspin. Immunostaining with phospho-specific antibodies in mammalian cells reveals mitotic phosphorylation at Thr3 of H3 in prophase and its dephosphorylation during anaphase (11).

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

Application Methods: Western Blotting

Background: Histone H2A.X is a variant histone that represents approximately 10% of the total H2A histone proteins in normal human fibroblasts (1). H2A.X is required for checkpoint-mediated cell cycle arrest and DNA repair following double-stranded DNA breaks (1). DNA damage, caused by ionizing radiation, UV-light, or radiomimetic agents, results in rapid phosphorylation of H2A.X at Ser139 by PI3K-like kinases, including ATM, ATR, and DNA-PK (2,3). Within minutes following DNA damage, H2A.X is phosphorylated at Ser139 at sites of DNA damage (4). This very early event in the DNA-damage response is required for recruitment of a multitude of DNA-damage response proteins, including MDC1, NBS1, RAD50, MRE11, 53BP1, and BRCA1 (1). In addition to its role in DNA-damage repair, H2A.X is required for DNA fragmentation during apoptosis and is phosphorylated by various kinases in response to apoptotic signals. H2A.X is phosphorylated at Ser139 by DNA-PK in response to cell death receptor activation, c-Jun N-terminal Kinase (JNK1) in response to UV-A irradiation, and p38 MAPK in response to serum starvation (5-8). H2A.X is constitutively phosphorylated on Tyr142 in undamaged cells by WSTF (Williams-Beuren syndrome transcription factor) (9,10). Upon DNA damage, and concurrent with phosphorylation of Ser139, Tyr142 is dephosphorylated at sites of DNA damage by recruited EYA1 and EYA3 phosphatases (9). While phosphorylation at Ser139 facilitates the recruitment of DNA repair proteins and apoptotic proteins to sites of DNA damage, phosphorylation at Tyr142 appears to determine which set of proteins are recruited. Phosphorylation of H2A.X at Tyr142 inhibits the recruitment of DNA repair proteins and promotes binding of pro-apoptotic factors such as JNK1 (9). Mouse embryonic fibroblasts expressing only mutant H2A.X Y142F, which favors recruitment of DNA repair proteins over apoptotic proteins, show a reduced apoptotic response to ionizing radiation (9). Thus, it appears that the balance of H2A.X Tyr142 phosphorylation and dephosphorylation provides a switch mechanism to determine cell fate after DNA damage.

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

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

Background: Modulation of chromatin structure plays a critical role in the regulation of transcription in eukaryotes. The nucleosome, made up of four core histone proteins (H2A, H2B, H3 and H4), is the primary building block of chromatin. In addition to the growing number of post-translational histone modifications regulating chromatin structure, cells can also exchange canonical histones with variant histones that can directly or indirectly modulate chromatin structure (1). There are five major variants of histone H2A: canonical H2A (most abundant), H2A.X, MacroH2A, H2ABbd and H2A.Z (2). Histone H2A.Z, the most conserved variant across species, functions as both a positive and negative regulator of transcription and is important for chromosome stability (2). Several homologous protein complexes, such as SWR-C (S. cerevisiae), TIP60 (D. melanogaster) and SRCAP (mammals), have been shown to catalyze the ATP-dependent exchange of H2A.Z for H2A in the nucleosome (3,4,5). This exchange of histone H2A variants changes histone-histone interactions in the nucleosome core and alters an acidic patch on the surface of the nucleosome, resulting in changes in nucleosome stability and binding of non-histone proteins such as HP1α (6,7).

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

Application Methods: Western Blotting

Background: The nucleosome, made up of four core histone proteins (H2A, H2B, H3, and H4), is the primary building block of chromatin. Originally thought to function as a static scaffold for DNA packaging, histones have now been shown to be dynamic proteins, undergoing multiple types of post-translational modifications, including acetylation, phosphorylation, methylation, and ubiquitination (1,2). The p300/CBP histone acetyltransferases acetylate multiple lysine residues in the amino terminal tail of histone H2B (Lys5, 12, 15, and 20) at gene promoters during transcriptional activation (1-3). Hyper-acetylation of the histone tails neutralizes the positive charge of these domains and is believed to weaken histone-DNA and nucleosome-nucleosome interactions, thereby destabilizing chromatin structure and increasing the access of DNA to various DNA-binding proteins (4,5). In addition, acetylation of specific lysine residues creates docking sites that facilitate recruitment of many transcription and chromatin regulatory proteins that contain a bromodomain, which binds to acetylated lysine residues (6). Histone H2B is mono-ubiquitinated at Lys120 during transcriptional activation by the RAD6 E2 protein in conjunction with the BRE1A/BRE1B E3 ligase (also known as RNF20/RNF40) (7). Mono-ubiquitinated histone H2B Lys120 is associated with the transcribed region of active genes and stimulates transcriptional elongation by facilitating FACT-dependent chromatin remodeling (7-9). In addition, it is essential for subsequent methylation of histone H3 Lys4 and Lys79, two additional histone modifications that regulate transcriptional initiation and elongation (10). In response to metabolic stress, AMPK is recruited to responsive genes and phosphorylates histone H2B at Lys36, both at promoters and in transcribed regions of genes, and may regulate transcriptional elongation (11). In response to multiple apoptotic stimuli, histone H2B is phosphorylated at Ser14 by the Mst1 kinase (12). Upon induction of apoptosis, Mst1 is cleaved and activated by caspase-3, leading to global phosphorylation of histone H2B during chromatin condensation. Interestingly, histone H2B is rapidly phosphorylated at irradiation-induced DNA damage foci in mouse embryonic fibroblasts (13). In this case, phosphorylation at Ser14 is rapid, depends on prior phosphorylation of H2AX Ser139, and occurs in the absence of apoptosis, suggesting that Ser14 phosphorylation may have distinct roles in DNA-damage repair and apoptosis.

$303
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Western Blotting

Background: Chondroblastoma is a rare type of benign tumor that is found at the rounded ends of the long bones in the arms and legs. More than 90% of chondroblastomas have been found to contain a heterozygous mutation in the H3F3A gene encoding the histone variant H3.3 (1). This mutation, a lysine to methionine amino acid substitution in codon 36 (K36M), inhibits at least two histone H3 lysine 36 methyltransferases, WHSC1 (MMSET) and SETD2, resulting in the reduction of global levels of histone H3 lysine 36 methylation (1). Chondrocytes containing the histone H3 K36M mutation exhibit several hallmarks of cancer cells, including increased ability to form colonies, resistance to apoptosis, and defects in differentiation. Reduction of global methylation levels in chondrocytes, resulting from the K36M mutation, contributes to tumorigenesis by altering the expression of cancer-associated genes. The histone H3 K36M mutation is also found to promote sarcomagenesis by impairing the differentiation of mesenchymal progenitor cells, resulting in undifferentiated sarcomas (2). The K36M mutation alters the histone methylation landscape, resulting in a genome-wide gain in histone H3 lysine 27 methylation and redistribution of polycomb respressive complex 1 and derepression of its target genes known to block mesenchymal differentiation. Finally, the histone H3 K36M mutation is also found in 13% of HPV-negative head and neck squamous cell carinomas, again contributing to tumorigenesis by altering global methylation levels of histone H3 lysine 36 (3).