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Antibody Sampler Kit Negative Regulation of Jnk Cascade

Background: Autophagy is a catabolic process for the autophagosome-lysosomal degradation of bulk cytoplasmic contents (1, 2). Selective autophagy targets the degradation of distinct sets of substrates and organelles (3-5). One of the best studied examples of selective autophagy involves the clearance of damaged mitochondria through a process called mitophagy. Several pathways have been described for various contexts of mitophagy, including the FUNDC1 pathway, the BNIP3 and BNIP3L/Nix pathway, and the PINK1/Parkin pathway. FUNDC1 is a mitochondrial protein that is phosphorylated by the autophagy kinase ULK1 and regulates hypoxia induced mitophagy (6, 7). BNIP3L/Nix and BNIP3 are members of the Bcl-2 family of apoptosis regulators that are expressed on mitochondria, induced by hypoxia, and have have been shown to play a role in mitophagy (8). BNIP3L/Nix is also important in the autophagic maturation of erythroid cells (9). FUNDC1, BNIP3 and BNIP3L/Nix bind to LC3 family members, targeting the mitochondria to the autophagosome.Non-hypoxic induction of mitophagy can be regulated by the PINK1/Parkin pathway, which plays causative roles in neurodegenerative disease, most notably Parkinson’s disease (10, 11). PINK1 is a mitochondrial serine/threonine kinase that is stabilized on the outer mitochondrial membrane of damaged mitochondria. Substrates of PINK1 include the E3 ubiquitin ligase Parkin and ubiquitin itself (12-14). Phosphorylation of Parkin as well as binding to phosphorylated ubiquitin leads to accumulation of ubiquitinated chains on multiple mitochondrial proteins. Ubiquitinated proteins are recognized by selective cargo receptors including SQSTM1/p62, Optineurin, and NDP52 (15-16). Autophagy cargo receptors contain an LC3-interacting region (LIR) required for binding to Atg8/LC3 family members and targeting to the autophagosome (3).

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 Phospho-EGF Receptor Pathway Sampler Kit provides an economical means to evaluate the activation status of multiple members of the EGF receptor pathway, including phosphorylated EGF receptor, Stat5, c-Cbl, Shc, Gab1, PLCγ1, Akt and p44/42 MAPK. The kit includes enough primary and secondary antibodies to perform two western blot experiments.

Background: The epidermal growth factor (EGF) receptor is a transmembrane tyrosine kinase that belongs to the HER/ErbB protein family. Ligand binding results in receptor dimerization, autophosphorylation, activation of downstream signaling, internalization, and lysosomal degradation (1,2). Phosphorylation of EGF receptor (EGFR) at Tyr845 in the kinase domain is implicated in stabilizing the activation loop, maintaining the active state enzyme, and providing a binding surface for substrate proteins (3,4). c-Src is involved in phosphorylation of EGFR at Tyr845 (5). The SH2 domain of PLCγ binds at phospho-Tyr992, resulting in activation of PLCγ-mediated downstream signaling (6). Phosphorylation of EGFR at Tyr1045 creates a major docking site for the adaptor protein c-Cbl, leading to receptor ubiquitination and degradation following EGFR activation (7,8). The GRB2 adaptor protein binds activated EGFR at phospho-Tyr1068 (9). A pair of phosphorylated EGFR residues (Tyr1148 and Tyr1173) provide a docking site for the Shc scaffold protein, with both sites involved in MAP kinase signaling activation (2). Phosphorylation of EGFR at specific serine and threonine residues attenuates EGFR kinase activity. EGFR carboxy-terminal residues Ser1046 and Ser1047 are phosphorylated by CaM kinase II; mutation of either of these serines results in upregulated EGFR tyrosine autophosphorylation (10).

The Insulin/IGF-1 Signaling Pathway Antibody Sampler Kit provides an economical means of detecting select components involved in the insulin and/or IGF-1 signaling pathways. The kit contains enough primary antibodies to perform at least two western blot experiments per antibody.

Background: Insulin and IGF-1 act on two closely related tyrosine kinase receptors to initiate a cascade of signaling events. These signaling events activate a variety of biological molecules, including kinases and transcription factors, which regulate cell growth, survival and metabolism.Type I insulin-like growth factor receptor (IGF-IR) is a transmembrane receptor tyrosine kinase that is widely expressed in many cell lines and cell types within fetal and postnatal tissues (1-3). Three tyrosine residues within the kinase domain (Tyr1131, Tyr1135, and Tyr1136) are the earliest major autophosphorylation sites (4). Phosphorylation of these three tyrosine residues is necessary for kinase activation (5,6). Insulin receptors (IRs) share significant structural and functional similarity with IGF-I receptors, including the presence of an equivalent tyrosine cluster (Tyr1146/1150/1151) within the kinase domain activation loop. Tyrosine autophosphorylation of IRs is one of the earliest cellular responses to insulin stimulation (7). Autophosphorylation begins with phosphorylation at Tyr1146 and either Tyr1150 or Tyr1151, while full kinase activation requires triple tyrosine phosphorylation (8).Akt, also referred to as PKB or Rac, plays a critical role in controlling survival and apoptosis (9-11). This protein kinase is activated by insulin and various growth and survival factors to function in a wortmannin-sensitive pathway involving PI3 kinase (10,11). Akt is activated by phospholipid binding and activation loop phosphorylation at Thr308 by PDK1 (12) 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 (13,14).Tuberin is a product of the TSC2 tumor suppressor gene and an important regulator of cell proliferation and tumor development (15). Tuberin is phosphorylated on Ser939 and Thr1462 in response to PI3K activation and the human TSC complex is a direct biochemical target of the PI3K/Akt pathway (16). This result complements Drosophila genetics studies suggesting the possible involvement of the tuberin-hamartin complex in the PI3K/Akt mediated insulin pathway (17-19).The mammalian target of rapamycin (mTOR, FRAP, RAFT) is a Ser/Thr protein kinase (20-22) that functions as an ATP and amino acid sensor to balance nutrient availability and cell growth (23,24). When sufficient nutrients are available, mTOR responds to a phosphatidic acid-mediated signal to transmit a positive signal to p70 S6 kinase and participate in the inactivation of the eIF4E inhibitor, 4E-BP1 (25). These events result in the translation of specific mRNA subpopulations. mTOR is phosphorylated at Ser2448 via the PI3 kinase/Akt signaling pathway and autophosphorylated at Ser2481 (26,27).The Forkhead family of transcription factors is involved in tumorigenesis of rhabdomyosarcoma and acute leukemias (28-30). Within the family, three members (FoxO1, FoxO4, and FoxO3a) have sequence similarity to the nematode orthologue DAF-16, which mediates signaling via a pathway involving IGFR1, PI3K, and Akt (31-33). Active forkhead members act as tumor suppressors by promoting cell cycle arrest and apoptosis. Increased proliferation results when forkhead transcription factors are inactivated through phosphorylation by Akt at Thr24, Ser256, and Ser319, which results in nuclear export and inhibition of transcription factor activity (34).Glycogen synthase kinase-3 (GSK-3) was initially identified as an enzyme that regulates glycogen synthesis in response to insulin (35). 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 (36,37).

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 Microglia Interferon-Related Module Antibody Sampler Kit provides an economical means of detecting proteins identified as markers of interferon-related microglial activity by western blot and/or immunofluorescence.

Background: Distinct microglial activation states have been identified using RNA-seq data from a vast array of neurological disease and aging models. These activation states have been categorized into modules corresponding to proliferation, neurodegeneration, interferon-relation, LPS-relation, and many others (1). Previous work identifying markers of specific brain cell types using RNA-seq has shown HS1 and ASC/TMS1 to be useful and specific tools to study microglia (2). HS1 is a protein kinase substrate that is expressed only in tissues and cells of hematopoietic origin (3) and ASC/TMS1 has been found to be a critical component of inflammatory signaling where it associates with and activates caspase-1 in response to pro-inflammatory signals (4).

The Parkinson's Research Antibody Sampler Kit provides an economical means of detecting target proteins related to Parkinson's disease. The kit contains enough primary and secondary antibody to perform two western blots per primary.
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 PDGF Receptor Activation Antibody Sampler Kit provides an economical means to evaluate the activation status of multiple members of the PDGF receptor pathway, including SHP-2, Akt, and p44/42 MAPK (Erk1/2). The kit includes enough antibody to perform two western blot experiments per primary antibody.
Akt Isoform Specific Antibody Sampler Kit provides an economical means of distinguishing between the three Akt isoforms, Akt1, Akt2 and Akt3, as well as a pan-Akt antibody. The kit provides 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 Phospho-Akt Isoform Antibody Sampler Kit provides an economical means of detecting the activation of Akt family members using phospho-specific and control antibodies. The kit contains enough primary antibodies to perform at least two western blot experiments per antibody.

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 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 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 I HDAC Antibody Sampler Kit provides an economical means of detecting Class I HDAC proteins using control antibodies against HDAC1, HDAC2 and HDAC3. 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 Rho-GTPase Antibody Sampler Kit contains reagents to examine aspects of cell migration, adhesion, proliferation and differentiation in cells. This kit includes enough primary and secondary antibodies to perform two Western blot experiments per each primary antibody.
The Necroptosis Antibody Sampler Kit provides an economical means of detecting total and phosphorylated proteins associated with necroptosis. The kit includes enough antibody to perform two western blots with each primary antibody.

Background: Necroptosis, a regulated pathway for necrotic cell death, is triggered by a number of inflammatory signals, including cytokines in the tumor necrosis factor (TNF) family, pathogen sensors such as toll-like receptors (TLRs), ischemic injury, and neurodegenerative diseases (1-3). The process is negatively regulated by caspases and is initiated through a complex containing the RIP and RIP3 kinases, typically referred to as the necrosome. Necroptosis is inhibited by a small molecule inhibitor of RIP, necrostatin-1 (Nec-1) (4). RIP is phosphorylated at several sites within the kinase domain that are sensitive to Nec-1, including Ser14, Ser15, Ser161, and Ser166 (5). During necroptosis, RIP3 is phosphorylated at Ser227, leading to recruitment and phosphorylation of MLKL at Thr357 and Ser358 (6). Phosphorylation of MLKL results in its oligomerization and translocation to the plasma membrane, where it effects membrane integrity (7-10).

The Toll-like Receptor Antibody Sampler Kit II provides an economical means of detecting expression of various Toll-like receptors (TLRs). The kit contains enough primary and secondary antibodies to perform at least two western blot experiments.

Background: Members of the Toll-like receptor (TLR) family, named for the closely related Toll receptor in Drosophila, play a pivotal role in innate immune responses (1-4). TLRs recognize conserved motifs found in various pathogens and mediate defense responses (5-7). TLR1, TLR2, TLR4, TLR5, TLR6, and TLR11 are localized to the plasma membrane, while TLR3, TLR7, TLR8, and TLR9 are localized to intracellular membranes including endosomal membranes. Triggering of the TLR pathway leads to the activation of NF-κB and subsequent regulation of immune and inflammatory genes (4). The TLRs and members of the IL-1 receptor family share a conserved stretch of approximately 200 amino acids known as the Toll/Interleukin-1 receptor (TIR) domain (1). Upon activation, TLRs associate with a number of cytoplasmic adaptor proteins containing TIR domains, including myeloid differentiation factor 88 (MyD88), MyD88-adaptor-like/TIR-associated protein (MAL/TIRAP), Toll-receptor-associated activator of interferon (TRIF), and Toll-receptor-associated molecule (TRAM) (8-10). This association leads to the recruitment and activation of IRAK1 and IRAK4, which form a complex with TRAF6 to activate TAK1 and IKK (8,11-14). Activation of IKK leads to the degradation of IκB, which normally maintains NF-κB in an inactive state by sequestering it in the cytoplasm. TLR1 and TLR6 associate with TLR2 to cooperatively mediate response to bacterial lipoproteins and fungal zymosan (6,15). TLR3 is an endosomal TLR that recognizes double-stranded RNA derived from viruses (7). TLR7 and TLR8 recognize single-stranded viral RNA and are also activated by synthetic imidazoquinoline compounds including R-848 (16,17). TLR9 recognizes unmethylated CpG motifs present on bacterial DNA (18).

The Actin Nucleation and Polymerization Antibody Sampler Kit provides an economical means to evaluate the presence and status of actin nucleation and polymerization. The kit contains enough primary antibody to perform two western blots per primary.
The Apoptosis/Necroptosis Antibody Sampler Kit provides an economical means of detecting markers for apoptosis and necroptosis. The kit contains enough primary antibody to perform at least two western blot experiments.

Background: Apoptosis is a regulated physiological process leading to cell death (1,2). Caspases, a family of cysteine acid proteases, are central regulators of apoptosis. Caspases are synthesized as inactive zymogens containing a pro-domain followed by large (p20) and small subunits (p10) that are proteolytically processed in a cascade of caspase activity. Initiator caspases (including 8, 9, 10, and 12) are closely coupled to proapoptotic signals. Once activated, these caspases cleave and activate downstream effector caspases (including 3, 6, and 7), which in turn cleave cytoskeletal and nuclear proteins like PARP, α-fodrin, DFF, and lamin A, and induce apoptosis. Cytochrome c released from mitochondria is coupled to the activation of caspase-9, a key initiator caspase. Apoptosis induced through the extrinsic mechanisms involving death receptors in the tumor necrosis factor receptor superfamily activates caspase-8. Activated caspase-8 cleaves and activates downstream effector caspases, such as caspase-1, -3, -6, and -7. Caspase-3 is a critical executioner of apoptosis, as it is either partially or totally responsible for the proteolytic cleavage of many key proteins, such as the nuclear enzyme poly (ADP-ribose) polymerase (PARP).Necroptosis, a regulated pathway for necrotic cell death, is triggered by a number of inflammatory signals, including cytokines in the tumor necrosis factor (TNF) family, pathogen sensors such as toll-like receptors (TLRs), and ischemic injury (3,4). Necroptosis is negatively regulated by caspase-8 mediated apoptosis in which the kinase RIP/RIPK1 is cleaved (5). Furthermore, necroptosis is inhibited by a small molecule inhibitor of RIP, necrostatin-1 (Nec-1) (6). Research studies show that necroptosis contributes to a number of pathological conditions, and Nec-1 has been shown to provide neuroprotection in models such as ischemic brain injury (7). RIP is phosphorylated at several sites within the kinase domain that are sensitive to Nec-1, including Ser14, Ser15, Ser161, and Ser166 (8). Phosphorylation drives association with RIP3, which is required for necroptosis (9-11). Mixed lineage kinase domain-like protein (MLKL) is a pseudokinase that was identified as downstream target of RIP3 in the necroptosis pathway (12). During necroptosis RIP3 is phosphorylated at Ser227, which recruits MLKL and leads to its phosphorylation at Thr357 and Ser358 (12). Knockdown of MLKL through multiple mechanisms results in inhibition of necroptosis (13). While the precise mechanism for MLKL-induced necroptosis is unclear, some studies have shown that necroptosis leads to oligomerization of MLKL and translocation to the plasma membrane, where it effects membrane integrity (14-17).

The Senescence Marker Antibody Sampler Kit provides an economical means of detecting multiple markers of cellular senescence. The kit includes enough antibody to perform two western blot experiments with each primary antibody.

Background: Senescence is characterized by stable stress-induced proliferative arrest and resistance to mitogenic stimuli, as well as the secretion of proteins such as cytokines, growth factors and proteases. These secreted proteins comprise the senescence-associated secretory phenotype (SASP). Senescent cells are thought to accumulate as an organism ages, and contribute to age-related diseases, including cancer, through promotion of inflammation and disruption of normal cellular function (1,2).Because there is no single biomarker that can be used to definitively identify senescent cells, researchers must rely on a collection of biomarkers commonly associated with senescence. The Senescence Marker Antibody Sampler Kit provides a collection of antibodies to commonly used biomarkers of senescence-associated cell cycle arrest (p16 INK4A, p21 Waf1/Cip1), senescence-associated DNA damage (gamma-Histone H2A.X), and the SASP (HMGB1, IL-6, TNF-alpha, MMP3). The kit also includes an antibody to Lamin B1, which is frequently reduced in senescent cells.