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Antibody Sampler Kit Regulation of Protein Binding

The Aurora Antibody Sampler Kit provides an economical means to investigate the G2/M phase of the cell cycle. The kit contains enough primary and secondary antibodies to perform two western blots with each antibody.

Background: Aurora kinases belong to a highly conserved family of mitotic serine/threonine kinases with three members identified among mammals: Aurora A, B, and C (1,2). Studies on the temporal expression pattern and subcellular localization of Aurora kinases in mitotic cells suggest an association with mitotic structure. Aurora kinase functional influences span from G2 phase to cytokinesis and may be involved in key cell cycle events such as centrosome duplication, chromosome bi-orientation and segregation, cleavage furrow positioning, and ingression (3). Aurora A is detected at the centrosomes, along mitotic spindle microtubules, and in the cytoplasm of mitotically proliferating cells. Aurora A protein levels are low during G1 and S phases and peak during the G2/M phase of the cell cycle. Phosphorylation of Aurora A at Thr288 in its catalytic domain increases kinase activity. Aurora A is involved in centrosome separation, maturation, and spindle assembly and stability. Expression of Aurora B protein also peaks during the G2/M phase of the cell cycle; Aurora B kinase activity peaks at the transition from metaphase to the end of mitosis. Aurora B associates with chromosomes during prophase prior to relocalizing to the spindle at anaphase. Aurora B regulates chromosome segregation through the control of microtubule-kinetochore attachment and cytokinesis. Expression of both Aurora A and Aurora B during the G2/M phase transition is tightly coordinated with histone H3 phosphorylation (4,5); research investigators have observed overexpression of these kinases in a variety of human cancers (2,4). Aurora C localizes to the centrosome from anaphase to cytokinesis and both mRNA and protein levels peak during G2/M phase. Although typical Aurora C expression is limited to the testis, research studies report overexpression of Aurora C is detected in various cancer cell lines (6).

The Neuronal Marker IF Antibody Sampler Kit provides an economical means for labeling neuronal structures by immunofluorescence (IF-F). This kit includes enough primary antibody to perform at least forty IF-F tests or two western blot experiments per primary antibody.
The GSK-3 Antibody Sampler Kit contains primary and secondary antibodies to perform two Western blots with each antibody.

Background: Glycogen synthase kinase-3 (GSK-3) was initially identified as an enzyme that regulates glycogen synthesis in response to insulin (1). GSK-3 is a ubiquitously expressed serine/threonine protein kinase that phosphorylates and inactivates glycogen synthase. GSK-3 is a critical downstream element of the PI3K/Akt cell survival pathway whose activity can be inhibited by Akt-mediated phosphorylation at Ser21 of GSK-3α and Ser9 of GSK-3β (2,3). GSK-3 has been implicated in the regulation of cell fate in Dictyostelium and is a component of the Wnt signaling pathway required for Drosophila, Xenopus, and mammalian development (4). GSK-3 has been shown to regulate cyclin D1 proteolysis and subcellular localization (5).

The TCF/LEF Family Antibody Sampler Kit provides an economical means of detecting total protein from the TCF/LEF1 family members. The kit contains enough primary and secondary antibodies to perform two Western blots with each antibody.
The β-Amyloid Antibody Sampler Kit provides an economical means of detecting APP and APP unmodified/modified fragments using total and fragment-specific antibodies. The kit includes enough antibody to perform two western blot experiments with each primary antibody.

Background: Amyloid β (Aβ) precursor protein (APP) is a 100-140 kDa transmembrane glycoprotein that exists as several isoforms (1). The amino acid sequence of APP contains an amyloid domain, which can be processed and released by two-step proteolytic cleavage (1). The extracellular deposition and accumulation of the released Aβ fragments form the main components of amyloid plaques in Alzheimer's disease (1). Several fragments corresponding to progressive APP processing at alternative cleavage sites have been identified (2). These include Aβ (1-37), Aβ (1-39), Aβ (1-40), and Aβ (1-42) (2). These fragments can also be N-terminally modified to generate pyroglutamate-3 Aβ (pE3-peptide) (3). Fragment-specific and pan-Aβ antibodies are used to detect and examine relative levels of individual Aβ fragments.

The ALK Activation Antibody Sampler Kit provides an economical means to evaluate the activation status of multiple members of the ALK pathway, including phosphorylated ALK, Jak2, Jak3, Stat3, Stat5, PLCγ1, Akt, Src, and p44/42 MAPK. The kit includes enough antibody to perform two western blot experiments with each primary antibody.

Background: Anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor for pleiotrophin (PTN), a growth factor involved in embryonic brain development (1-3). In ALK-expressing cells, PTN induces phosphorylation of both ALK and the downstream effectors IRS-1, Shc, PLCγ, and PI3 kinase (1). ALK was originally discovered as a nucleophosmin (NPM)-ALK fusion protein produced by a translocation (4). Investigators have found that the NPM-ALK fusion protein is a constitutively active, oncogenic tyrosine kinase associated with anaplastic lymphoma (4). Research literature suggests that activation of PLCγ by NPM-ALK may be a crucial step for its mitogenic activity and involved in the pathogenesis of anaplastic lymphomas (5).A distinct ALK oncogenic fusion protein involving ALK and echinoderm microtubule-associated protein like 4 (EML4) has been described in the research literature from a non-small cell lung cancer (NSCLC) cell line, with corresponding fusion transcripts present in some cases of lung adenocarcinoma. The short, amino-terminal region of the microtubule-associated protein EML4 is fused to the kinase domain of ALK (6-8).

The Src Family Antibody Sampler Kit provides an economical means of evaluating total levels of Src family member proteins. The kit contains enough primary and secondary antibody to perform two western blots with each antibody.

Background: The Src family of protein tyrosine kinases, which includes Src, Lyn, Fyn, Yes, Lck, Blk, and Hck, are important in the regulation of growth and differentiation of eukaryotic cells (1). Src activity is regulated by tyrosine phosphorylation at two sites, but with opposing effects. While phosphorylation at Tyr416 in the activation loop of the kinase domain upregulates enzyme activity, phosphorylation at Tyr527 in the carboxy-terminal tail by Csk renders the enzyme less active (2).

The Phospho-MAPK Family Antibody Sampler Kit provides an economical means of evaluating the phosphorylation state of p38, p44/42, and SAPK/JNK mitogen-activated protein kinases. The kit contains enough primary and secondary antibodies to perform two western blot experiments.

Background: p44/42 MAPK (Erk1/2), SAPK/JNK, and p38 MAPK function in protein kinase cascades that play a critical role in the regulation of cell growth, differentiation, and control of cellular responses to cytokines and stress. p44/42 MAPK is activated by growth and neurotrophic factors. Activation occurs through phosphorylation of threonine and tyrosine residues (Thr202 and Tyr204 in human Erk1) at the sequence T*EY* by a single upstream MAP kinase kinase (MEK). SAPK/JNK and p38 MAPK are activated by inflammatory cytokines and by a wide variety of cellular stresses. Activation of SAPK/JNK occurs via phosphorylation at Thr183 and Tyr185 by the dual specificity enzyme SEK/MKK4. Both MKK3 and SEK phosphorylate p38 MAPK on tyrosine and threonine at the sequence T*GY* to activate p38 MAP kinase (1-5).

The Phospho-SAPK/JNK Pathway Antibody Sampler Kit provides a fast and economical means of evaluating multiple members of the SAPK/JNK pathway as well as their activation state. The kit contains enough primary and secondary antibodies to perform two Western blot experiments.

Background: The stress-activated protein kinase/Jun-amino-terminal kinase SAPK/JNK is potently and preferentially activated by a variety of environmental stresses including UV and gamma radiation, ceramides, inflammatory cytokines, and in some instances, growth factors and GPCR agonists (1-6). As with the other MAPKs, the core signaling unit is composed of a MAPKKK, typically MEKK1-MEKK4, or by one of the mixed lineage kinases (MLKs), which phosphorylate and activate MKK4/7. Upon activation, MKKs phosphorylate and activate the SAPK/JNK kinase (2). Stress signals are delivered to this cascade by small GTPases of the Rho family (Rac, Rho, cdc42) (3). Both Rac1 and cdc42 mediate the stimulation of MEKKs and MLKs (3). Alternatively, MKK4/7 can be activated in a GTPase-independent mechanism via stimulation of a germinal center kinase (GCK) family member (4). There are three SAPK/JNK genes each of which undergoes alternative splicing, resulting in numerous isoforms (3). SAPK/JNK, when active as a dimer, can translocate to the nucleus and regulate transcription through its effects on c-Jun, ATF-2, and other transcription factors (3,5).

The Phospho-Akt Pathway Antibody Sampler Kit provides an economical means to evaluate the activation status of the Akt signaling pathway, including PTEN and phosphorylated Akt, GSK-3beta, c-Raf and PDK1. The kit includes enough primary and secondary antibodies to perform two Western blot experiments.

Background: Akt, also referred to as PKB or Rac, plays a critical role in controlling survival and apoptosis (1-3). This protein kinase is activated by insulin and various growth and survival factors to function in a wortmannin-sensitive pathway involving PI3 kinase (2,3). Akt is activated by phospholipid binding and activation loop phosphorylation at Thr308 by PDK1 (4) and by phosphorylation within the carboxy terminus at Ser473. The previously elusive PDK2 responsible for phosphorylation of Akt at Ser473 has been identified as mammalian target of rapamycin (mTOR) in a rapamycin-insensitive complex with rictor and Sin1 (5,6). Akt promotes cell survival by inhibiting apoptosis through phosphorylation and inactivation of several targets, including Bad (7), forkhead transcription factors (8), c-Raf (9), and caspase-9. PTEN phosphatase is a major negative regulator of the PI3 kinase/Akt signaling pathway (10). LY294002 is a specific PI3 kinase inhibitor (11). Another essential Akt function is the regulation of glycogen synthesis through phosphorylation and inactivation of GSK-3α and β (12,13). Akt may also play a role in insulin stimulation of glucose transport (12). In addition to its role in survival and glycogen synthesis, Akt is involved in cell cycle regulation by preventing GSK-3β-mediated phosphorylation and degradation of cyclin D1 (14) and by negatively regulating the cyclin dependent kinase inhibitors p27 Kip1 (15) and p21 Waf1/Cip1 (16). Akt also plays a critical role in cell growth by directly phosphorylating mTOR in a rapamycin-sensitive complex containing raptor (17). More importantly, Akt phosphorylates and inactivates tuberin (TSC2), an inhibitor of mTOR within the mTOR-raptor complex (18,19).

The MAPK Family Antibody Sampler Kit provides an economical means of evaluating total levels of p38, p44/42, and SAPK/JNK mitogen-activated protein kinases. The kit contains enough primary and secondary antibody to perform two western blot experiments.

Background: p44/42 MAPK (Erk1/2), SAPK/JNK, and p38 MAPK function in protein kinase cascades that play a critical role in the regulation of cell growth, differentiation, and control of cellular responses to cytokines and stress. p44/42 MAPK is activated by growth and neurotrophic factors. Activation occurs through phosphorylation of threonine and tyrosine residues (Thr202 and Tyr204 in human Erk1) at the sequence T*EY* by a single upstream MAP kinase kinase (MEK). SAPK/JNK and p38 MAPK are activated by inflammatory cytokines and by a wide variety of cellular stresses. Activation of SAPK/JNK occurs via phosphorylation at Thr183 and Tyr185 by the dual specificity enzyme SEK/MKK4. Both MKK3 and SEK phosphorylate p38 MAPK on tyrosine and threonine at the sequence T*GY* to activate p38 MAP kinase (1-5).

The SET1/COMPASS Antibody Sampler Kit provides an economical means of detecting SET1/COMPASS proteins using control antibodies against SET1A, SET1B, MLL1, MLL2, WDR5, WDR82, and Menin. This kit contains enough primary antibodies to perform at least two western blot experiments.

Background: The Set1 histone methyltransferase protein was first identified in yeast as part of the Set1/COMPASS histone methyltransferase complex, which methylates histone H3 on lysine 4 and functions as a transcriptional co-activator (1). While yeast contain only one known Set1 protein, mammals contain six Set1-related proteins: SET1A, SET1B, MLL1, MLL2, MLL3 and MLL4, all of which methylate histone H3 on lysine 4 (2,3). These Set1-related proteins are each found in distinct protein complexes, all of which share the common core structural subunits WDR5, RBBP5 and ASH2L (2-6). WDR82 is a core subunit specific to SET1A and SET1B complexes, while Menin is a core subunit specific to the MLL complexes (4,5,7).Like yeast Set1, all six Set1-related mammalian proteins methylate histone H3 on lysine 4 (2-6). SET1A, SET1B, MLL1 and MLL2 mediate di- and tri-methylation of histone H3 Lys4 at gene promoters to facilitate transcription activation. MLL3 and MLL4 function primarily to mono-methylate histone H3 Lys4 at gene enhancers. MLL1 and MLL2 function as master regulators of both embryogenesis and hematopoiesis, and are required for proper expression of Hox genes (8-10). MLL1 is a large approximately 4000 amino acid protein that is cleaved by the Taspase 1 threonine endopeptidase to form N-terminal (MLL1-N) and C-terminal MLL1 (MLL1-C) fragments, both of which are subunits of the functional MLL1/COMPASS complex (11,12). MLL1 translocations are found in a large number of hematological malignancies, suggesting that Set1 histone methyltransferase complexes play a critical role in leukemogenesis (6). Like MLL1, MLL2 is also a large, approximately 2700 amino acid protein that is cleaved by the Taspase 1 threonine endopeptidase to form N-terminal (MLL2-N) and C-terminal (MLL2-C) fragments, both of which are subunits of the functional MLL2/COMPASS complex. MLL2 has also been implicated as a modulator of hematological malignancies (13). MLL3 and MLL4 proteins are not cleaved by Taspase 1.

The Innate Immunity Activation Antibody Sampler Kit provides an economical means of detecting the activation of multiple signaling pathways involved in innate immunity using phospho-specific, cleavage-specific, and control antibodies. The kit contains enough primary antibodies to perform at least two western blot experiments.

Background: The innate immune system responds rapidly to pathogens by detecting conserved pathogen-associated molecular patterns (PAMPs) and damage/danger-associated molecular patterns (DAMPs) through pattern recognition receptors (PRRs). There are several families of PRRs. Toll-like receptors (TLRs) are transmembrane PRRs and signal through recruitment of adaptor proteins, including MyD88, which leads to recruitment and phosphorylation of IRAK1 and IRAK4, followed by activation of NF-κB and MAP kinases (1-3). Some TLRs also activate IRFs, which upregulate the type I interferon response. Activation of TLR3 and TLR4 results in phosphorylation and activation of IRF-3, while TLR7, TLR8, and TLR9 lead to activation of IRF-7 (2, 3). STING is a multi-pass ER transmembrane protein that is activated in response to intracellular DNA downstream of DNA-sensing cytoplasmic PRRs, such as DDX41, or by binding the second messenger cyclic-GMP-AMP (cGAMP) produced by cGAS (4-6). Following activation, STING translocates with TBK1 to perinuclear endosomes, leading to phosphorylation and activation of IRF-3 and NF-κB (7, 8). Following activation and translocation, STING gets phosphorylated by ULK1, resulting in STING inactivation and degradation (9). Inflammasomes are cytoplasmic multimeric protein complexes that assemble in response to PAMPs or DAMPs detected by AIM2 or members of the nod-like receptor (NLR) family, such as NLRP3 (10). Inflammasomes activate Caspase-1, which cleaves the IL-1β and IL-18 precursor proteins into the mature forms (10).

The Pathological Hallmarks of Alzheimer's Disease Antibody Sampler Kit provides an economical means of detecting the activation of Tau and APP family members using phospho-specific, and control antibodies for both proteins. The kit includes enough antibodies to perform two western blot experiments with each primary antibody.

Background: Tau is a heterogeneous microtubule-associated protein that promotes and stabilizes microtubule assembly, especially in axons. Six isoforms with different amino-terminal inserts and different numbers of tandem repeats near the carboxy terminus have been identified, and tau is hyperphosphorylated at approximately 25 sites by ERK, GSK-3, and CDK5 (1,2). Phosphorylation decreases the ability of tau to bind to microtubules. Neurofibrillary tangles are a major hallmark of Alzheimer's disease; these tangles are bundles of paired helical filaments composed of hyperphosphorylated tau. In particular, phosphorylation at Ser396 by GSK-3 or CDK5 destabilizes microtubules. Furthermore, research studies have shown that inclusions of tau are found in a number of other neurodegenerative diseases, collectively known as tauopathies (1,3). The cerebrospinal fluid concentration of tau phosphorylated at Thr181 has been proposed to be a biomarker for the study of neurodegenerative disorders (4).Amyloid β (Aβ) precursor protein (APP) is a 100-140 kDa transmembrane glycoprotein that exists as several isoforms (4). The amino acid sequence of APP contains the amyloid domain, which can be released by a two-step proteolytic cleavage (4). The extracellular deposition and accumulation of the released Aβ fragments form the main components of amyloid plaques in Alzheimer's disease (4). APP can be phosphorylated at several sites, which may affect the proteolytic processing and secretion of this protein (5-8). Aβ-43 has been suggested as a biomarker in early onset of Alzheimer's disease, where patients have lower levels of Aβ-43 in cerebrospinal fluid (8-10). Several studies have shown that Aβ toxicity of Aβ-43 is as high as Aβ-42 or Aβ-40 in different models of Alzheimer's disease, including mouse models and human disease (10).

The Wnt Signaling Antibody Sampler Kit provides an economical means of detecting integral proteins within the Wnt signaling pathway. The kit contains enough primary and secondary antibody to perform two Western blots with each.
The γ Secretase Antibody Sampler Kit provides an economical means of evaluating components of the gamma secretase complex. The kit contains enough primary and secondary antibodies to perform two western miniblot experiments.
The Angiogenesis Antibody Sampler Kit provides an economical means to investigate the angiogenic pathway downstream of VEGFR2. The kit contains enough primary antibody to perform two western blots per primary antibody.
The Histone Deacetylase (HDAC) Antibody Sampler Kit provides a fast and economical means to evaluate the endogenous levels of HDACs. The kit contains enough primary and secondary antibodies to perform two Western blot experiments.

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).

The Class II HDAC Antibody Sampler Kit provides an economical means of detecting Class II HDAC proteins using control antibodies against HDAC4, HDAC5, HDAC6, and HDAC7. The kit contains enough primary antibodies to perform at least two western blot experiments.

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).

The ER Stress-induced Antibody Sampler Kit contains reagents to investigate ER stress-induced signaling within the cell. The kit contains enough primary antibodies to perform four western blot experiments per primary antibody.