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Product listing: ATM (D2E2) Rabbit mAb, UniProt ID Q13315 #2873 to Phospho-Rb (Ser795) Antibody, UniProt ID P06400 #9301

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

Application Methods: Western Blotting

Background: Ataxia telangiectasia mutated kinase (ATM) is a serine/threonine kinase that regulates cell cycle checkpoints and DNA repair (1). Activation of ATM by autophosphorylation on Ser1981 occurs in response to exposed DNA double stranded breaks. ATM kinase regulates a number of proteins involved in cell cycle checkpoint control, apoptosis, and DNA repair. Known substrates include p53, Chk2, Chk1, CtIP, 4E-BP1, BRCA1, RPA3, H2A.X, SMC1, FANCD2, Rad17, Artemis, Nbs1, and the I-2 regulatory subunit of PP1 (1,2). Mutations in the corresponding ATM gene result in ataxia telangiectasia (AT), an autosomal recessive disease characterized by uncoordinated muscle movement and neurodegeneration. Cells from AT patients display defective DNA damage-induced checkpoint activation, sensitivity to radiation, and a higher frequency of chromosome breakage (3,4).

$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: The breast cancer susceptibility proteins BRCA1 and BRCA2 are frequently mutated in cases of hereditary breast and ovarian cancers and have roles in multiple processes related to DNA damage, repair, cell cycle progression, transcription, ubiquitination, and apoptosis (1-4). BRCA2 has been shown to be required for localization of Rad51 to sites of double stranded breaks (DSBs) in DNA, and cells lacking BRCA1 and BRCA2 cannot repair DSBs through the Rad51-dependent process of homologous recombination (HR) (5). Numerous DNA damage-induced phosphorylation sites on BRCA1 have been identified, including Ser988, 1189, 1387, 1423, 1457, 1524, and 1542, and kinases activated in a cell cycle-dependent manner, including Aurora A and CDK2, can also phosphorylate BRCA1 at Ser308 and Ser1497, respectively (6-10). Cell cycle-dependent phosphorylation of BRCA2 at Ser3291 by CDKs has been proposed as a mechanism to switch off HR as cells progress beyond S-phase by blocking the carboxy terminal Rad51 binding site (11).

$260
100 µl
APPLICATIONS
REACTIVITY
All Species Expected

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

Background: Halogenated nucleotides such as the pyrimidine analog bromodeoxyuridine (BrdU) are useful for labeling nascent DNA in living cells and tissues. BrdU becomes incorporated into replicating DNA in place of thymidine and subsequent immunodetection of BrdU using specific monoclonal antibodies allows labeling of cells in S phase of the cell cycle. After pulse-labeling cells or tissues with bromodeoxyuridine, BrdU (Bu20a) Mouse mAb can be used to detect BrdU incorporated into single stranded DNA. Please see our detailed protocol for information regarding the labeling procedure and denaturation of double stranded DNA for various immunodetection applications (1-4).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey

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

Background: The initiation of DNA replication in mammalian cells is a highly coordinated process that ensures duplication of the genome only once per cell division cycle. Origins of replication are dispersed throughout the genome, and their activities are regulated via the sequential binding of prereplication and replication factors. The origin recognition complex (ORC) is thought to be bound to chromatin throughout the cell cycle (1,2). The prereplication complex (Pre-RC) forms in late mitosis/early G1 phase beginning with the binding of CDT1 and cdc6 to the origin, which allows binding of the heterohexameric MCM2-7 complex. The MCM complex is thought to be the replicative helicase, and formation of the pre-RC is referred to as chromatin licensing. Subsequent initiation of DNA replication requires the activation of the S-phase promoting kinases CDK2 and cdc7. Cdc7, which is active only in complex with its regulatory subunit dbf4, phosphorylates MCM proteins bound to chromatin and allows binding of the replication factor cdc45 and DNA polymerase (3,4).Binding of CDT1 to geminin prevents pre-RC formation, and expression and degradation of geminin serve to regulate CDT1 activity (reviewed in 5). The interaction of CDT1 with MCM proteins is important in pre-RC formation and licensing (6,7). Both cdc6 and CDT1 are degraded by the ubiquitin proteasome pathway in response to DNA damage associated with rereplication (8).

$122
20 µl
$293
100 µl
APPLICATIONS
REACTIVITY
Human, Rat

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

Background: Cyclins are a family of proteins that activate specific cyclin-dependent kinases required for progression through the cell cycle. The entry of all eukaryotic cells into mitosis is regulated by activation of cdc2/cdk1 at the G2/M transition. This activation is a multi-step process that begins with the binding of the regulatory subunit, cyclin B1, to cdc2/cdk1 to form the mitosis-promoting factor (MPF). MPF remains in the inactive state until phosphorylation of cdc2/cdk1 at Thr161 by cdk activating kinase (CAK) (1,2) and dephosphorylation of cdc2/cdk1 at Thr14/Tyr15 by cdc25C (3-5). Five cyclin B1 phosphorylation sites (Ser116, 126, 128, 133, and 147) are located in the cytoplasmic retention signal (CRS) domain and are thought to regulate the translocation of cyclin B1 to the nucleus at the G2/M checkpoint, promoting nuclear accumulation and initiation of mitosis (6-9). While MPF itself can phosphorylate Ser126 and Ser128, polo-like kinase 1 (PLK1) phosphorylates cyclin B1 preferentially at Ser133 and possibly at Ser147 (6,10). At the end of mitosis, cyclin B1 is targeted for degradation by the anaphase-promoting complex (APC), allowing for cell cycle progression (11). Research studies have shown that cyclin B1 is overexpressed in breast, prostate, and non-small cell lung cancers (12-14).

$305
50 tests
100 µl
Cell Signaling Technology Antibody conjugated to Alexa Fluor®647 fluorescent dye and tested in-house for direct Flow Cytometric analysis of human cells. The unconjugated antibody #4135 reacts with, among others, human, mouse and hamster Cyclin B1. CST expects that Cyclin B1 Mouse mAb (Alexa Fluor®647 conjugate) will also recognize Cyclin B1 in these species.
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Flow Cytometry

Background: Cyclins are a family of proteins that activate specific cyclin-dependent kinases required for progression through the cell cycle. The entry of all eukaryotic cells into mitosis is regulated by activation of cdc2/cdk1 at the G2/M transition. This activation is a multi-step process that begins with the binding of the regulatory subunit, cyclin B1, to cdc2/cdk1 to form the mitosis-promoting factor (MPF). MPF remains in the inactive state until phosphorylation of cdc2/cdk1 at Thr161 by cdk activating kinase (CAK) (1,2) and dephosphorylation of cdc2/cdk1 at Thr14/Tyr15 by cdc25C (3-5). Five cyclin B1 phosphorylation sites (Ser116, 126, 128, 133, and 147) are located in the cytoplasmic retention signal (CRS) domain and are thought to regulate the translocation of cyclin B1 to the nucleus at the G2/M checkpoint, promoting nuclear accumulation and initiation of mitosis (6-9). While MPF itself can phosphorylate Ser126 and Ser128, polo-like kinase 1 (PLK1) phosphorylates cyclin B1 preferentially at Ser133 and possibly at Ser147 (6,10). At the end of mitosis, cyclin B1 is targeted for degradation by the anaphase-promoting complex (APC), allowing for cell cycle progression (11). Research studies have shown that cyclin B1 is overexpressed in breast, prostate, and non-small cell lung cancers (12-14).

$111
20 µl
$260
100 µl
APPLICATIONS
REACTIVITY
Human

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

Background: Ki-67, named after the location where it was discovered (Kiel University, Germany), is a nuclear nonhistone protein (1) that is universally expressed among proliferating cells and absent in quiescent cells (2). Ki-67 detects proliferating cells in G1, S, G2, and mitosis, but not in the G0 resting phase. Research studies have shown that high levels of Ki-67 are associated with poorer breast cancer survival (3). Research studies have explored the use of Ki-67, along with other markers, as potential prognostic or predictive markers in breast cancer and other malignant diseases (4).

$111
20 µl
$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Immunohistochemistry (Paraffin)

Background: Ki-67, named after the location where it was discovered (Kiel University, Germany), is a nuclear nonhistone protein (1) that is universally expressed among proliferating cells and absent in quiescent cells (2). Ki-67 detects proliferating cells in G1, S, G2, and mitosis, but not in the G0 resting phase. Research studies have shown that high levels of Ki-67 are associated with poorer breast cancer survival (3). Research studies have explored the use of Ki-67, along with other markers, as potential prognostic or predictive markers in breast cancer and other malignant diseases (4).

$305
50 tests
100 µl
This Cell Signaling Technology antibody is conjugated to Alexa Fluor® 488 fluorescent dye and tested in-house for direct flow cytometric and immunofluorescent analysis in human cells. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated Ki-67 (D3B5) Rabbit mAb #9129.
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Flow Cytometry, Immunofluorescence (Frozen), Immunofluorescence (Immunocytochemistry)

Background: Ki-67, named after the location where it was discovered (Kiel University, Germany), is a nuclear nonhistone protein (1) that is universally expressed among proliferating cells and absent in quiescent cells (2). Ki-67 detects proliferating cells in G1, S, G2, and mitosis, but not in the G0 resting phase. Research studies have shown that high levels of Ki-67 are associated with poorer breast cancer survival (3). Research studies have explored the use of Ki-67, along with other markers, as potential prognostic or predictive markers in breast cancer and other malignant diseases (4).

$305
50 tests
100 µl
This Cell Signaling Technology antibody is conjugated to Alexa Fluor® 647 fluorescent dye and tested in-house for direct flow cytometric and immunofluorescent analysis in human and rat cells. The antibody is expected to exhibit the same species cross-reactivity as the unconjugated Ki-67 (D3B5) Rabbit mAb #9129.
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Flow Cytometry, Immunofluorescence (Frozen), Immunofluorescence (Immunocytochemistry)

Background: Ki-67, named after the location where it was discovered (Kiel University, Germany), is a nuclear nonhistone protein (1) that is universally expressed among proliferating cells and absent in quiescent cells (2). Ki-67 detects proliferating cells in G1, S, G2, and mitosis, but not in the G0 resting phase. Research studies have shown that high levels of Ki-67 are associated with poorer breast cancer survival (3). Research studies have explored the use of Ki-67, along with other markers, as potential prognostic or predictive markers in breast cancer and other malignant diseases (4).

$111
20 µl
$260
100 µl
APPLICATIONS
REACTIVITY
Mouse

Application Methods: Immunohistochemistry (Paraffin)

Background: Ki-67, named after the location where it was discovered (Kiel University, Germany), is a nuclear nonhistone protein (1) that is universally expressed among proliferating cells and absent in quiescent cells (2). Ki-67 detects proliferating cells in G1, S, G2, and mitosis, but not in the G0 resting phase. Research studies have shown that high levels of Ki-67 are associated with poorer breast cancer survival (3). Research studies have explored the use of Ki-67, along with other markers, as potential prognostic or predictive markers in breast cancer and other malignant diseases (4).

$305
50 tests
100 µl
This Cell Signaling Technology antibody is conjugated to phycoerythrin (PE) and tested in-house for direct flow cytometry analysis in human cells. The antibody is expected to exhibit the same species cross-reactivity as the unconjugated Ki-67 (D3B5) Rabbit mAb #9129.
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Flow Cytometry

Background: Ki-67, named after the location where it was discovered (Kiel University, Germany), is a nuclear nonhistone protein (1) that is universally expressed among proliferating cells and absent in quiescent cells (2). Ki-67 detects proliferating cells in G1, S, G2, and mitosis, but not in the G0 resting phase. Research studies have shown that high levels of Ki-67 are associated with poorer breast cancer survival (3). Research studies have explored the use of Ki-67, along with other markers, as potential prognostic or predictive markers in breast cancer and other malignant diseases (4).

$111
20 µl
$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Immunoprecipitation, Western Blotting

Background: Members of the INK4 family of cyclin dependent kinase inhibitors include p16INK4A, p15INK4B, p18INK4C and p19INK4D. The INK4 family members inhibit cyclin dependent kinases 4 and 6 (CDK4 and CDK6), causing cell cycle arrest in G1 phase. The INK4A-ARF-INK4B locus on chromosome 9p21, frequently lost in human cancer, encodes the INK4 family members p16INK5A and p15INK4B, as well as the unrelated protein, ARF (1).p16 INK4A expression, typically repressed in the absence of stress, is thought to drive cells into senescence, and p16 INK4A expression is a commonly used marker of senescent cells (2). p16INK4A protein expression is often altered in human cancer (3,4), and high expression is currently used as a predictive biomarker in cervical cancer (5).

$305
50 tests
100 µl
This Cell Signaling Technology antibody is conjugated to Alexa Fluor® 647 fluorescent dye and tested in-house for direct flow cytometric analysis in human cells. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated p16 INK4A (D7C1M) Rabbit mAb #80772.
APPLICATIONS
REACTIVITY
Human

Application Methods: Flow Cytometry

Background: Members of the INK4 family of cyclin dependent kinase inhibitors include p16INK4A, p15INK4B, p18INK4C and p19INK4D. The INK4 family members inhibit cyclin dependent kinases 4 and 6 (CDK4 and CDK6), causing cell cycle arrest in G1 phase. The INK4A-ARF-INK4B locus on chromosome 9p21, frequently lost in human cancer, encodes the INK4 family members p16INK5A and p15INK4B, as well as the unrelated protein, ARF (1).p16 INK4A expression, typically repressed in the absence of stress, is thought to drive cells into senescence, and p16 INK4A expression is a commonly used marker of senescent cells (2). p16INK4A protein expression is often altered in human cancer (3,4), and high expression is currently used as a predictive biomarker in cervical cancer (5).

$305
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 monkey cells. The antibody is expected to exhibit the same species cross-reactivity as the unconjugated p21 Waf1/Cip1 (12D1) Rabbit mAb #2947.
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Flow Cytometry, Immunofluorescence (Immunocytochemistry)

Background: The tumor suppressor protein p21 Waf1/Cip1 acts as an inhibitor of cell cycle progression. It functions in stoichiometric relationships forming heterotrimeric complexes with cyclins and cyclin-dependent kinases. In association with CDK2 complexes, it serves to inhibit kinase activity and block progression through G1/S (1). However, p21 may also enhance assembly and activity in complexes of CDK4 or CDK6 and cyclin D (2). The carboxy-terminal region of p21 is sufficient to bind and inhibit PCNA, a subunit of DNA polymerase, and may coordinate DNA replication with cell cycle progression (3). Upon UV damage or during cell cycle stages when cdc2/cyclin B or CDK2/cyclin A are active, p53 is phosphorylated and upregulates p21 transcription via a p53-responsive element (4). Protein levels of p21 are downregulated through ubiquitination and proteasomal degradation (5).

$260
100 µg
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: The p53 tumor suppressor protein plays a major role in cellular response to DNA damage and other genomic aberrations. Activation of p53 can lead to either cell cycle arrest and DNA repair or apoptosis (1). p53 is phosphorylated at multiple sites in vivo and by several different protein kinases in vitro (2,3). DNA damage induces phosphorylation of p53 at Ser15 and Ser20 and leads to a reduced interaction between p53 and its negative regulator, the oncoprotein MDM2 (4). MDM2 inhibits p53 accumulation by targeting it for ubiquitination and proteasomal degradation (5,6). p53 can be phosphorylated by ATM, ATR, and DNA-PK at Ser15 and Ser37. Phosphorylation impairs the ability of MDM2 to bind p53, promoting both the accumulation and activation of p53 in response to DNA damage (4,7). Chk2 and Chk1 can phosphorylate p53 at Ser20, enhancing its tetramerization, stability, and activity (8,9). p53 is phosphorylated at Ser392 in vivo (10,11) and by CAK in vitro (11). Phosphorylation of p53 at Ser392 is increased in human tumors (12) and has been reported to influence the growth suppressor function, DNA binding, and transcriptional activation of p53 (10,13,14). p53 is phosphorylated at Ser6 and Ser9 by CK1δ and CK1ε both in vitro and in vivo (13,15). Phosphorylation of p53 at Ser46 regulates the ability of p53 to induce apoptosis (16). Acetylation of p53 is mediated by p300 and CBP acetyltransferases. Inhibition of deacetylation suppressing MDM2 from recruiting HDAC1 complex by p19 (ARF) stabilizes p53. Acetylation appears to play a positive role in the accumulation of p53 protein in stress response (17). Following DNA damage, human p53 becomes acetylated at Lys382 (Lys379 in mouse) in vivo to enhance p53-DNA binding (18). Deacetylation of p53 occurs through interaction with the SIRT1 protein, a deacetylase that may be involved in cellular aging and the DNA damage response (19).

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

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

Background: Proliferating cell nuclear antigen (PCNA) is a member of the DNA sliding clamp family of proteins that assist in DNA replication (1). Crystal structure data suggests that a PCNA homotrimer ring can encircle and slide along the DNA double helix (2). Multiple proteins involved in DNA replication, DNA repair, and cell cycle control bind to PCNA rather than directly associating with DNA, thus facilitating fast processing of DNA (reviewed in 3). PCNA protein expression is a well-accepted marker of proliferation.

$122
20 µl
$303
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: Ataxia telangiectasia mutated kinase (ATM) is a serine/threonine kinase that regulates cell cycle checkpoints and DNA repair (1). Activation of ATM by autophosphorylation on Ser1981 occurs in response to exposed DNA double stranded breaks. ATM kinase regulates a number of proteins involved in cell cycle checkpoint control, apoptosis, and DNA repair. Known substrates include p53, Chk2, Chk1, CtIP, 4E-BP1, BRCA1, RPA3, H2A.X, SMC1, FANCD2, Rad17, Artemis, Nbs1, and the I-2 regulatory subunit of PP1 (1,2). Mutations in the corresponding ATM gene result in ataxia telangiectasia (AT), an autosomal recessive disease characterized by uncoordinated muscle movement and neurodegeneration. Cells from AT patients display defective DNA damage-induced checkpoint activation, sensitivity to radiation, and a higher frequency of chromosome breakage (3,4).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Immunoprecipitation, Western Blotting

Background: At least 4 distinct polo-like kinases exist in mammalian cells: PLK1, PLK2, PLK3 and PLK4/SAK (1). Like the other PLK family members, PLK3 contains an amino-terminal catalytic domain and a conserved carboxy-terminal domain termed the Polo box (2). PLK3, also called proliferation-related kinase (Prk) (3), was originally described as a fibroblast growth factor (FGF)-inducible kinase (Fnk) and identified as an immediate-early response gene responsive to FGF-1 and other mitogens (4). PLK3 is a cytokine-inducible serine/threonine kinase whose protein expression is cell cycle regulated. Though its expression is found primarily in G1 phase of the cell cycle, PLK3 is detected in G0 and in late telophase prior to cytokinesis (5). Like the other PLK family members, PLK3 functions mainly as a regulator of the cell cycle. Specifically, PLK3 is required for entry into S phase and is a critical regulator of G1 events, as indicated by RNAi-induced PLK3-depleted cells (2). PLK3 is also involved in the regulation of DNA damage response via phosphorylation of p53 on Ser20 (6). PLK3 may act as a tumor suppressor as Plk3-deficient mice develop spontaneous tumors in various organs (7). Unlike PLK1, PLK3 expression is down regulated in cancers including lung (3), head and neck (8), and colon (9).

$269
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Flow Cytometry, IHC-Leica® Bond™, Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting

Background: SLFN11 is a nuclear protein that belongs to the Schlafen (SLFN) family of genes involved in cell cycle regulation and growth inhibition (1, 2). Expression of SLFN11 predicts sensitivity of cancer cell lines to DNA-damaging agents (1, 3). Evidence suggests that in the presence of DNA-targeted therapies, SLFN11 is recruited to stressed replication forks where it blocks replication leading to cell death (4). SLFN11 is being explored as a predictive biomarker for response to DNA-targeted therapies (5).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Western Blotting

Background: The cdc25 protein phosphatase family plays a critical role in activating cyclin-dependent kinases (CDKs) via dephosphorylation of conserved Thr14/Tyr15 inhibitory phosphorylation sites. While cdc25C is primarily responsible for activating CDK1 to overcome the G2/M checkpoint and allow mitotic entry, the primary substrate of cdc25A is CDK2, which, when active, allows progression through the G1/S and intra-S checkpoints (1). Abundance, subcellular localization and activity of cdc25A is tightly controlled by a variety of mechanisms, including phosphorylation, ubiquitination, and inhibitory binding to 14-3-3 proteins. During normal cell cycle progression, elevated c-Myc and E2F transcription factor levels lead to increased cdc25A expression (2). When conditions are favorable for DNA synthesis, cdc25A and CDK2 form an activation loop, wherein each activates the other enzyme (1). DNA damage, on the other hand, leads to multisite phosphorylation at inhibitory sites (Ser123, Ser177, Ser278, Ser292, and Thr506) by Chk1 and Chk2, which result in 14-3-3 binding and ubiquitin-mediated degradation (3,4).

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

Application Methods: Immunofluorescence (Immunocytochemistry), Western Blotting

Background: Cyclins are a family of proteins that activate specific cyclin-dependent kinases required for progression through the cell cycle. The entry of all eukaryotic cells into mitosis is regulated by activation of cdc2/cdk1 at the G2/M transition. This activation is a multi-step process that begins with the binding of the regulatory subunit, cyclin B1, to cdc2/cdk1 to form the mitosis-promoting factor (MPF). MPF remains in the inactive state until phosphorylation of cdc2/cdk1 at Thr161 by cdk activating kinase (CAK) (1,2) and dephosphorylation of cdc2/cdk1 at Thr14/Tyr15 by cdc25C (3-5). Five cyclin B1 phosphorylation sites (Ser116, 126, 128, 133, and 147) are located in the cytoplasmic retention signal (CRS) domain and are thought to regulate the translocation of cyclin B1 to the nucleus at the G2/M checkpoint, promoting nuclear accumulation and initiation of mitosis (6-9). While MPF itself can phosphorylate Ser126 and Ser128, polo-like kinase 1 (PLK1) phosphorylates cyclin B1 preferentially at Ser133 and possibly at Ser147 (6,10). At the end of mitosis, cyclin B1 is targeted for degradation by the anaphase-promoting complex (APC), allowing for cell cycle progression (11). Research studies have shown that cyclin B1 is overexpressed in breast, prostate, and non-small cell lung cancers (12-14).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Immunoprecipitation, Western Blotting

Background: Activity of the cyclin-dependent kinases CDK4 and CDK6 is regulated by T-loop phosphorylation, by the abundance of their cyclin partners (the D-type cyclins), and by association with CDK inhibitors of the Cip/Kip or INK family of proteins (1). The inactive ternary complex of cyclin D/CDK4 and p27 Kip1 requires extracellular mitogenic stimuli for the release and degradation of p27 concomitant with a rise in cyclin D levels to affect progression through the restriction point and Rb-dependent entry into S-phase (2). The active complex of cyclin D/CDK4 targets the retinoblastoma protein for phosphorylation, allowing the release of E2F transcription factors that activate G1/S-phase gene expression (3). Levels of cyclin D protein drop upon withdrawal of growth factors through downregulation of protein expression and phosphorylation-dependent degradation (4).

$260
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Chromatin IP, Western Blotting

Background: The E2F transcription factors are essential for regulation of the cell cycle (1,2). Physiological E2F is a heterodimer composed of an E2F subunit together with a DP subunit (3, 4). Six members of the E2F family have been identified, and each E2F subunit has a DNA binding and a dimerization domain. E2F-1 to -5 activate transcription. E2F-1 to -3 bind pRb, and E2F-4 and -5 bind p107 or p130, and these interactions are under cell cycle control (5-8). E2F-1 has oncogenic properties in vivo and in vitro. E2F-1 can induce apoptosis through p53-dependent and -independent mechanisms. E2F-1 is stress-responsive, and is regulated by a PI3-kinase-like kinase family such as the ATM/ATR kinases (9-11).

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

Application Methods: Chromatin IP, Immunoprecipitation, Western Blotting

Background: The p53 tumor suppressor protein plays a major role in cellular response to DNA damage and other genomic aberrations. Activation of p53 can lead to either cell cycle arrest and DNA repair or apoptosis (1). p53 is phosphorylated at multiple sites in vivo and by several different protein kinases in vitro (2,3). DNA damage induces phosphorylation of p53 at Ser15 and Ser20 and leads to a reduced interaction between p53 and its negative regulator, the oncoprotein MDM2 (4). MDM2 inhibits p53 accumulation by targeting it for ubiquitination and proteasomal degradation (5,6). p53 can be phosphorylated by ATM, ATR, and DNA-PK at Ser15 and Ser37. Phosphorylation impairs the ability of MDM2 to bind p53, promoting both the accumulation and activation of p53 in response to DNA damage (4,7). Chk2 and Chk1 can phosphorylate p53 at Ser20, enhancing its tetramerization, stability, and activity (8,9). p53 is phosphorylated at Ser392 in vivo (10,11) and by CAK in vitro (11). Phosphorylation of p53 at Ser392 is increased in human tumors (12) and has been reported to influence the growth suppressor function, DNA binding, and transcriptional activation of p53 (10,13,14). p53 is phosphorylated at Ser6 and Ser9 by CK1δ and CK1ε both in vitro and in vivo (13,15). Phosphorylation of p53 at Ser46 regulates the ability of p53 to induce apoptosis (16). Acetylation of p53 is mediated by p300 and CBP acetyltransferases. Inhibition of deacetylation suppressing MDM2 from recruiting HDAC1 complex by p19 (ARF) stabilizes p53. Acetylation appears to play a positive role in the accumulation of p53 protein in stress response (17). Following DNA damage, human p53 becomes acetylated at Lys382 (Lys379 in mouse) in vivo to enhance p53-DNA binding (18). Deacetylation of p53 occurs through interaction with the SIRT1 protein, a deacetylase that may be involved in cellular aging and the DNA damage response (19).

$122
20 µl
$303
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: The breast cancer susceptibility proteins BRCA1 and BRCA2 are frequently mutated in cases of hereditary breast and ovarian cancers and have roles in multiple processes related to DNA damage, repair, cell cycle progression, transcription, ubiquitination, and apoptosis (1-4). BRCA2 has been shown to be required for localization of Rad51 to sites of double stranded breaks (DSBs) in DNA, and cells lacking BRCA1 and BRCA2 cannot repair DSBs through the Rad51-dependent process of homologous recombination (HR) (5). Numerous DNA damage-induced phosphorylation sites on BRCA1 have been identified, including Ser988, 1189, 1387, 1423, 1457, 1524, and 1542, and kinases activated in a cell cycle-dependent manner, including Aurora A and CDK2, can also phosphorylate BRCA1 at Ser308 and Ser1497, respectively (6-10). Cell cycle-dependent phosphorylation of BRCA2 at Ser3291 by CDKs has been proposed as a mechanism to switch off HR as cells progress beyond S-phase by blocking the carboxy terminal Rad51 binding site (11).

$122
20 µl
$303
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: The p53 tumor suppressor protein plays a major role in cellular response to DNA damage and other genomic aberrations. Activation of p53 can lead to either cell cycle arrest and DNA repair or apoptosis (1). p53 is phosphorylated at multiple sites in vivo and by several different protein kinases in vitro (2,3). DNA damage induces phosphorylation of p53 at Ser15 and Ser20 and leads to a reduced interaction between p53 and its negative regulator, the oncoprotein MDM2 (4). MDM2 inhibits p53 accumulation by targeting it for ubiquitination and proteasomal degradation (5,6). p53 can be phosphorylated by ATM, ATR, and DNA-PK at Ser15 and Ser37. Phosphorylation impairs the ability of MDM2 to bind p53, promoting both the accumulation and activation of p53 in response to DNA damage (4,7). Chk2 and Chk1 can phosphorylate p53 at Ser20, enhancing its tetramerization, stability, and activity (8,9). p53 is phosphorylated at Ser392 in vivo (10,11) and by CAK in vitro (11). Phosphorylation of p53 at Ser392 is increased in human tumors (12) and has been reported to influence the growth suppressor function, DNA binding, and transcriptional activation of p53 (10,13,14). p53 is phosphorylated at Ser6 and Ser9 by CK1δ and CK1ε both in vitro and in vivo (13,15). Phosphorylation of p53 at Ser46 regulates the ability of p53 to induce apoptosis (16). Acetylation of p53 is mediated by p300 and CBP acetyltransferases. Inhibition of deacetylation suppressing MDM2 from recruiting HDAC1 complex by p19 (ARF) stabilizes p53. Acetylation appears to play a positive role in the accumulation of p53 protein in stress response (17). Following DNA damage, human p53 becomes acetylated at Lys382 (Lys379 in mouse) in vivo to enhance p53-DNA binding (18). Deacetylation of p53 occurs through interaction with the SIRT1 protein, a deacetylase that may be involved in cellular aging and the DNA damage response (19).

$122
20 µl
$303
100 µl
APPLICATIONS
REACTIVITY
Human

Application Methods: Western Blotting

Background: PBK/TOPK is a serine/threonine kinase that is phosphorylated and active during mitosis (1). PBK/TOPK is composed of kinase subdomains and a carboxy-terminal PDZ-Binding domain, which is thought to interact with the tumor suppressor protein hDlg (1). Increased PBK/TOPK expression has been observed in highly proliferative malignant cell lines, and PBK/TOPK expression is strongly downregulated during terminal differentiation of HL-60 leukemic cells (2,3). PMA-induced kinase activity toward PBK/TOPK has been observed (4), and cdc2/cyclinB has been shown to phosphorylate PBK/TOPK in vitro, presumably at Thr9 (1). Potential substrates of PBK/TOPK include p38 MAPK and c-Myc (3,4).

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

Application Methods: Immunoprecipitation, Western Blotting

Background: The retinoblastoma tumor suppressor protein Rb regulates cell proliferation by controlling progression through the restriction point within the G1-phase of the cell cycle (1). Rb has three functionally distinct binding domains and interacts with critical regulatory proteins including the E2F family of transcription factors, c-Abl tyrosine kinase, and proteins with a conserved LXCXE motif (2-4). Cell cycle-dependent phosphorylation by a CDK inhibits Rb target binding and allows cell cycle progression (5). Rb inactivation and subsequent cell cycle progression likely requires an initial phosphorylation by cyclin D-CDK4/6 followed by cyclin E-CDK2 phosphorylation (6). Specificity of different CDK/cyclin complexes has been observed in vitro (6-8) and cyclin D1 is required for Ser780 phosphorylation in vivo (9).

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

Application Methods: Immunoprecipitation, Western Blotting

Background: The retinoblastoma tumor suppressor protein Rb regulates cell proliferation by controlling progression through the restriction point within the G1-phase of the cell cycle (1). Rb has three functionally distinct binding domains and interacts with critical regulatory proteins including the E2F family of transcription factors, c-Abl tyrosine kinase, and proteins with a conserved LXCXE motif (2-4). Cell cycle-dependent phosphorylation by a CDK inhibits Rb target binding and allows cell cycle progression (5). Rb inactivation and subsequent cell cycle progression likely requires an initial phosphorylation by cyclin D-CDK4/6 followed by cyclin E-CDK2 phosphorylation (6). Specificity of different CDK/cyclin complexes has been observed in vitro (6-8) and cyclin D1 is required for Ser780 phosphorylation in vivo (9).