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Product listing: Cell Cycle Regulation Antibody Sampler Kit, UniProt ID X10101 #9932 to Phospho-4E-BP1 (Thr70) Antibody, UniProt ID Q13541 #9455

Cell Cycle Regulation Antibody Sampler kit offers an economical way of detecting eight integral cell cycle regulation proteins. The kit contains enough primary and secondary antibodies to perform two western blot experiments with each primary antibody.

Background: Eukaryotic cell cycle progression is dependent, in part, on the tightly regulated activity of cyclin dependent kinases (CDKs). Cyclin D/CDK4/6 activity occurs in mid-late G1 phase, upstream of CDK2/cyclin E activity. Both of these activities are required for hyperphosphorylation of the retinoblastoma gene product (pRb). pRb phosphorylation allows the release of S phase-promoting transcription factors and is indicative of the cell's commitment to proliferate. This point in the cell cycle is known as the restriction point. Cyclin protein levels oscillate throughout the cell cycle, and their availability is a means of controlling CDK activity and cell proliferation. Cyclin D is degraded through the ubiquitin proteasome pathway in the absence of mitogenic signaling. Ubiquitination of cyclin D1 is enhanced by phosphorylation at Thr286 by glycogen synthase kinase 3b (GSK-3b) (1). p27/Kip1, p57 Kip2 and p21 Waf1/Cip1 are members of the Cip/Kip family of cyclin-dependent kinase inhibitors. They form heterotrimeric complexes with cyclins and CDKs, inhibiting kinase activity and blocking progression through G1/S phase (2). However, p21 may enhance assembly and activity of cyclin D/CDK4/6 complexes (3). Levels of p21 and p27 protein are controlled through ubiquitination and proteasomal degradation (4). Levels of p27 are upregulated in quiescent cells and in cells treated with negative cell cycle regulators. p27 nuclear localization is controlled by Akt-dependent phosphorylation at Thr157 (5). The inhibitors of CDK4 (INK4) family include p15 INK4B, p16 INK4A, p18 INK4C, and p19 INK4D. All INK4 proteins selectively inhibit CDK4/6 activity, either in a binary complex, or in a ternary complex including cyclin D, resulting in inhibition of cell division (6,7).

The Apoptosis Antibody Sampler Kit provides an economical means to evaluate the levels of inactive and active caspases. The kit contains enough primary and secondary antibodies to perform two Western blot experiments with each antibody.

Background: Apoptosis is a regulated physiological process leading to cell death. Caspases, a family of cysteine acid proteases, are central regulators of apoptosis. 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 (1). Proapoptotic stimuli include the FasL, TNF-α, DNA damage and ER stress. Fas and TNFR activate caspases 8 and 10 (2), DNA damage leads to the activation of caspase-9 and ER stress leads to the calcium-mediated activation of caspase-12 (3). The inhibitor of apoptosis protein (IAP) family includes XIAP and survivin and functions by binding and inhibiting several caspases (4,5). Smac/Diablo, a mitochondrial protein, is released into the cytosol upon mitochondrial stress and competes with caspases for binding of IAPs. The interaction of Smac/Diablo with IAPs relieves the inhibitory effects of the IAPs on caspases (6).

The KinomeView® Profiling Kit provides a set of Phospho-Motif Antibodies that cover a large portion of the kinome and react broadly with serine, threonine, and tyrosine phosphorylation mediated by diverse kinase families throughout the kinome. This kit will provide researchers with an immunoblotting strategy to dissect the complexity of the phosphoproteome and determine the kinase families involved in the regulation of diverse physiological processes. By using the provided Phospho-motif Antibodies, the investigator can assess global changes in protein phosphorylation by western analysis across a range of experimental samples and conditions.
$98
1000 ml
Phosphate Buffered Saline (PBS) solution with the detergent Tween® 20 for use as a wash buffer and diluent for ELISA. 1 X PBST contains 3.2 mM Na2HPO4, 0.5 mM KH2PO4, 1.3 mM KCl, 135 mM NaCl, 0.05% Tween® 20, pH 7.4.
$64
15 ml
Cell Lysis Buffer is used to lyse cells under nondenaturing conditions.
The Epithelial-Mesenchymal Transition (EMT) Antibody Sampler Kit provides an economical means of evaluating EMT. The kit contains enough primary antibody to perform two western blots per primary.
$111
20 µl
$260
200 µl
$630
600 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Immunoprecipitation, Western Blotting

Background: Apoptosis induced through the CD95 receptor (Fas/APO-1) and tumor necrosis factor receptor 1 (TNFR1) activates caspase-8 and leads to the release of the caspase-8 active fragments, p18 and p10 (1-3). Activated caspase-8 cleaves and activates downstream effector caspases such as caspase-1, -3, -6, and -7. Caspase-3 ultimately elicits the morphological hallmarks of apoptosis, including DNA fragmentation and cell shrinkage.

$260
100 µl
$630
300 µl
APPLICATIONS
REACTIVITY
Bovine, Human, Monkey, Mouse, Pig, Rat, Zebrafish

Application Methods: 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, Mouse, Rat

Application Methods: Flow Cytometry, Immunofluorescence (Frozen), Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting

Background: Vascular endothelial growth factor receptor 2 (VEGFR2, KDR, Flk-1) is a major receptor for VEGF-induced signaling in endothelial cells. Upon ligand binding, VEGFR2 undergoes autophosphorylation and becomes activated (1). Major autophosphorylation sites of VEGFR2 are located in the kinase insert domain (Tyr951/996) and in the tyrosine kinase catalytic domain (Tyr1054/1059) (2). Activation of the receptor leads to rapid recruitment of adaptor proteins, including Shc, GRB2, PI3 kinase, NCK, and the protein tyrosine phosphatases SHP-1 and SHP-2 (3). Phosphorylation at Tyr1212 provides a docking site for GRB2 binding and phospho-Tyr1175 binds the p85 subunit of PI3 kinase and PLCγ, as well as Shb (1,4,5). Signaling from VEGFR2 is necessary for the execution of VEGF-stimulated proliferation, chemotaxis and sprouting, as well as survival of cultured endothelial cells in vitro and angiogenesis in vivo (6-8).

$303
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Western Blotting

Background: Nitric oxide (NO) is implicated in carcinogenesis (1), chronic infection, inflammation (2) and neurodegeneration (3). High levels of both superoxide and nitric oxide in tissues interact to form peroxynitrite, a potent oxidant that can modify Tyr residues in proteins to form 3-nitro-tyrosine (4). Tyrosine nitration of mitochondrial manganese superoxide dismutase results in loss of enzymatic activity (4). The nitration of p53 at Tyr residues abolishes its capacity for binding to its DNA consensus sequence (5).

$248
400 µl
APPLICATIONS
REACTIVITY
All Species Expected, Human, Monkey, Mouse, Rat

Application Methods: Peptide ELISA (DELFIA), Western Blotting

Background: Acetylation of lysine, like phosphorylation of serine, threonine or tyrosine, is an important reversible modification controlling protein activity. The conserved amino-terminal domains of the four core histones (H2A, H2B, H3, and H4) contain lysines that are acetylated by histone acetyltransferases (HATs) and deacetylated by histone deacetylases (HDACs) (1). Signaling resulting in acetylation/deacetylation of histones, transcription factors, and other proteins affects a diverse array of cellular processes including chromatin structure and gene activity, cell growth, differentiation, and apoptosis (2-6). Recent proteomic surveys suggest that acetylation of lysine residues may be a widespread and important form of posttranslational protein modification that affects thousands of proteins involved in control of cell cycle and metabolism, longevity, actin polymerization, and nuclear transport (7,8). The regulation of protein acetylation status is impaired in cancer and polyglutamine diseases (9), and HDACs have become promising targets for anti-cancer drugs currently in development (10).

$168
50 µg
Molecular Weight:540.73 g/mol
APPLICATIONS
REACTIVITY
All Species Expected

Application Methods: Immunofluorescence (Immunocytochemistry)

$327
50 tests
100 µl
This Cell Signaling Technology antibody is conjugated to Alexa Fluor® 488 fluorescent dye and tested in-house for direct flow cytometry and immunofluorescent analysis in human cells. The antibody is expected to exhibit the same species cross-reactivity as the unconjugated Cleaved Caspase-3 (Asp175) Antibody #9661.
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Flow Cytometry, Immunofluorescence (Immunocytochemistry)

Background: Caspase-3 (CPP-32, Apoptain, Yama, SCA-1) 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) (1). Activation of caspase-3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments. Cleavage of caspase-3 requires the aspartic acid residue at the P1 position (2).

$111
20 µl
$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: Caspase-3 (CPP-32, Apoptain, Yama, SCA-1) 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) (1). Activation of caspase-3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments. Cleavage of caspase-3 requires the aspartic acid residue at the P1 position (2).

$122
20 µl
$323
100 µl
$755
300 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Flow Cytometry, Immunofluorescence (Immunocytochemistry), Immunohistochemistry (Frozen), Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting

Background: Caspase-3 (CPP-32, Apoptain, Yama, SCA-1) 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) (1). Activation of caspase-3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments. Cleavage of caspase-3 requires the aspartic acid residue at the P1 position (2).

$118
10 western blots
100 µl
Caspase-3 Control Cell Extracts (Jurkat Untreated): Untreated Jurkat cells are lysed in Chaps cell extract buffer and a cytoplasmic fraction is generated to serve as a negative control for caspase cleavage. Supplied in SDS sample buffer.Caspase-3 Control Cell Extracts (Jurkat +Cytochrome c): Untreated Jurkat cells are lysed in Chaps cell extract buffer and a cytoplasmic fraction is generated. Extracts are treated with cytochrome c in vitro to generate a positive control for caspase cleavage. Supplied in SDS sample buffer.
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: Caspase-3 (CPP-32, Apoptain, Yama, SCA-1) 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) (1). Activation of caspase-3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments. Cleavage of caspase-3 requires the aspartic acid residue at the P1 position (2).

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

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

Background: Caspase-3 (CPP-32, Apoptain, Yama, SCA-1) 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) (1). Activation of caspase-3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments. Cleavage of caspase-3 requires the aspartic acid residue at the P1 position (2).

$117
20 µl
$303
100 µl
$717
300 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Flow Cytometry, Immunofluorescence (Immunocytochemistry), Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting

Background: Caspase-3 (CPP-32, Apoptain, Yama, SCA-1) 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) (1). Activation of caspase-3 requires proteolytic processing of its inactive zymogen into activated p17 and p12 fragments. Cleavage of caspase-3 requires the aspartic acid residue at the P1 position (2).

$303
100 µl
APPLICATIONS
REACTIVITY
All Species Expected

Application Methods: Immunoprecipitation, Western Blotting

Background: Ataxia telangiectasia mutated kinase (ATM) and ataxia telangiectasia and Rad3-related kinase (ATR) are related kinases that regulate cell cycle checkpoints and DNA repair (1). The identified substrates for ATM are p53, p95/NBS1, MDM2, Chk2, BRCA1, CtIP, 4E-BP1, and Chk1 (1,2) The essential requirement for the substrates of ATM/ATR is S*/T*Q. Hydrophobic amino acids at positions -3 and -1, and negatively charged amino acids at position +1 are positive determinants for substrate recognition by these kinases. Positively charged residues surrounding the S*/T*Q are negative determinants for substrate phosphorylation (3). The complex phenotype of AT cells suggests that it likely has additional substrates (3). To better understand the kinase and identify substrates for ATM and the related kinase ATR, CST has developed antibodies that recognize phosphorylated serine or threonine in the S*/T*Q motif.

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

Application Methods: Western Blotting

Background: The ATP2A2 (SERCA2) calcium pump is one of several sarcoplasmic and endoplasmic reticulum Ca2+-ATPases responsible for regulating calcium transport across intracellular membranes (1). Multiple isoforms have been isolated, with ATP2A2a (SERCA2a) found predominantly in the sarcoplasmic reticulum of muscle cells and ATP2A2b (SERCA2b) more ubiquitously expressed in the endoplasmic reticulum of most cell types (2). An isoform containing a truncated carboxy region (ATP2A2c) is expressed in epithelial and hematopoietic cell lines and may be involved in monocyte differentiation (3). Post-translational modification of ATP2A2 (SERCA2), including phosphorylation and tyrosine nitration, modify Ca2+ -ATPase activity and calcium transport (4,5). Mutation in the corresponding ATP2A2 (SERCA2) gene results in Darier disease, a skin disorder characterized by the presence of dark, keratotic papules or rash found on the head and torso (6).

$303
100 µl
APPLICATIONS
REACTIVITY
D. melanogaster

Application Methods: Immunofluorescence (Immunocytochemistry), Western Blotting

Background: Cell death in the fruit fly Drosophila melanogaster is regulated by many of the same stimuli as mammalian cell death (1). The Drosophila genome contains seven caspase genes; three encode initiator caspases, and four encode effector caspases (reviewed in (2)). The Drosophila effector caspase, death caspase-1 (Dcp-1), is a critical executioner of apoptosis. It is involved in the proteolytic cleavage of many key proteins, such as the nuclear enzyme poly (ADP-ribose) polymerase (PARP). The activation of Dcp-1 requires proteolytic processing of its inactive zymogen into active p22 and p13 fragments (3). Comparison of the in vivo activity between DrICE and Dcp-1 has shown that DrICE is a more effective inducer of apoptosis than Dcp-1, which instead plays a role in determining the rate of cell death (4).

$303
100 µl
$717
300 µl
APPLICATIONS
REACTIVITY
Bovine, Human, Pig

Application Methods: Western Blotting

Background: Endothelial nitric-oxide synthase (eNOS) is an important enzyme in the cardiovascular system. It catalyzes the production of nitric oxide (NO), a key regulator of blood pressure, vascular remodeling, and angiogenesis (1,2). The activity of eNOS is regulated by phosphorylation at multiple sites. The two most thoroughly studied sites are the activation site Ser1177 and the inhibitory site Thr495 (3). Several protein kinases including Akt/PKB, PKA, and AMPK activate eNOS by phosphorylating Ser1177 in response to various stimuli (4,5). In contrast, bradykinin and H2O2 activate eNOS activity by promoting both Ser1177 phosphorylation and Thr495 dephosphorylation (6,7).

$260
100 µl
$630
300 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

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

Background: β-Catenin is a key downstream effector in the Wnt signaling pathway (1). It is implicated in two major biological processes in vertebrates: early embryonic development (2) and tumorigenesis (3). CK1 phosphorylates β-catenin at Ser45. This phosphorylation event primes β-catenin for subsequent phosphorylation by GSK-3β (4-6). GSK-3β destabilizes β-catenin by phosphorylating it at Ser33, Ser37, and Thr41 (7). Mutations at these sites result in the stabilization of β-catenin protein levels and have been found in many tumor cell lines (8).

$111
20 µl
$260
100 µl
$637
300 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

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

Background: PTEN (phosphatase and tensin homologue deleted on chromosome ten), also referred to as MMAC (mutated in multiple advanced cancers) phosphatase, is a tumor suppressor implicated in a wide variety of human cancers (1). PTEN encodes a 403 amino acid polypeptide originally described as a dual-specificity protein phosphatase (2). The main substrates of PTEN are inositol phospholipids generated by the activation of the phosphoinositide 3-kinase (PI3K) (3). PTEN is a major negative regulator of the PI3K/Akt signaling pathway (1,4,5). PTEN possesses a carboxy-terminal, noncatalytic regulatory domain with three phosphorylation sites (Ser380, Thr382, and Thr383) that regulate PTEN stability and may affect its biological activity (6,7). PTEN regulates p53 protein levels and activity (8) and is involved in G protein-coupled signaling during chemotaxis (9,10).

$122
20 µl
$303
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: PTEN (phosphatase and tensin homologue deleted on chromosome ten), also referred to as MMAC (mutated in multiple advanced cancers) phosphatase, is a tumor suppressor implicated in a wide variety of human cancers (1). PTEN encodes a 403 amino acid polypeptide originally described as a dual-specificity protein phosphatase (2). The main substrates of PTEN are inositol phospholipids generated by the activation of the phosphoinositide 3-kinase (PI3K) (3). PTEN is a major negative regulator of the PI3K/Akt signaling pathway (1,4,5). PTEN possesses a carboxy-terminal, noncatalytic regulatory domain with three phosphorylation sites (Ser380, Thr382, and Thr383) that regulate PTEN stability and may affect its biological activity (6,7). PTEN regulates p53 protein levels and activity (8) and is involved in G protein-coupled signaling during chemotaxis (9,10).

$111
20 µl
$260
100 µl
$630
300 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Western Blotting

Background: PARP, a 116 kDa nuclear poly (ADP-ribose) polymerase, appears to be involved in DNA repair in response to environmental stress (1). This protein can be cleaved by many ICE-like caspases in vitro (2,3) and is one of the main cleavage targets of caspase-3 in vivo (4,5). In human PARP, the cleavage occurs between Asp214 and Gly215, which separates the PARP amino-terminal DNA binding domain (24 kDa) from the carboxy-terminal catalytic domain (89 kDa) (2,4). PARP helps cells to maintain their viability; cleavage of PARP facilitates cellular disassembly and serves as a marker of cells undergoing apoptosis (6).

$111
20 µl
$261
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

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

Background: PARP, a 116 kDa nuclear poly (ADP-ribose) polymerase, appears to be involved in DNA repair in response to environmental stress (1). This protein can be cleaved by many ICE-like caspases in vitro (2,3) and is one of the main cleavage targets of caspase-3 in vivo (4,5). In human PARP, the cleavage occurs between Asp214 and Gly215, which separates the PARP amino-terminal DNA binding domain (24 kDa) from the carboxy-terminal catalytic domain (89 kDa) (2,4). PARP helps cells to maintain their viability; cleavage of PARP facilitates cellular disassembly and serves as a marker of cells undergoing apoptosis (6).

$303
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: Cdc25 is a protein phosphatase responsible for dephosphorylating and activating cdc2, a crucial step in regulating the entry of all eukaryotic cells into mitosis (1). cdc25C is constitutively phosphorylated at Ser216 throughout interphase by c-TAK1, while phosphorylation at this site is DNA damage-dependent at the G2/M checkpoint (2). When phosphorylated at Ser216, cdc25C binds to members of the 14-3-3 family of proteins, sequestering cdc25C in the cytoplasm and thereby preventing premature mitosis (3). The checkpoint kinases Chk1 and Chk2 phosphorylate cdc25C at Ser216 in response to DNA damage (4,5).

$122
20 µl
$303
100 µl
$717
300 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: The Forkhead family of transcription factors is involved in tumorigenesis of rhabdomyosarcoma and acute leukemias (1-3). 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 (4-6). Active forkhead members act as tumor suppressors by promoting cell cycle arrest and apoptosis. Increased expression of any FoxO member results in the activation of the cell cycle inhibitor p27 Kip1. Forkhead transcription factors also play a part in TGF-β-mediated upregulation of p21 Cip1, a process negatively regulated through PI3K (7). 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 (8). Forkhead transcription factors can also be inhibited by the deacetylase sirtuin (SirT1) (9).

$303
100 µl
$717
300 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: Translation repressor protein 4E-BP1 (also known as PHAS-1) inhibits cap-dependent translation by binding to the translation initiation factor eIF4E. Hyperphosphorylation of 4E-BP1 disrupts this interaction and results in activation of cap-dependent translation (1). Both the PI3 kinase/Akt pathway and FRAP/mTOR kinase regulate 4E-BP1 activity (2,3). Multiple 4E-BP1 residues are phosphorylated in vivo (4). While phosphorylation by FRAP/mTOR at Thr37 and Thr46 does not prevent the binding of 4E-BP1 to eIF4E, it is thought to prime 4E-BP1 for subsequent phosphorylation at Ser65 and Thr70 (5).