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Monoclonal Antibody Flow Cytometry Cell Differentiation

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

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

Background: Calcyclin-binding protein or Siah-1-interacting protein (CACYBP/SIP) is a component of the ubiquitin E3 ligase complex that also contains Siah1, Skp1, and Ebi (1). CACYBP regulates β-catenin turnover and plays an important role in thymocyte development (2). CACYBP also binds to tubulin and may be involved in cytoskeletal regulation (3,4). It is highly expressed in neurons, and its cellular localization may be regulated by Ca2+ (5,6). Retinoic acid treatment of the neuroblastoma cell line SH-SY5Y induces translocation of CACYBP to the nucleus and seems to be correlated with phosphorylation of CACYBP on serine residues (7). Recent studies also suggest that CACYBP may possess phosphatase activity (8), and that it can bind and dephosphorylate Erk1/2 (8,9).

$269
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey, Mouse, Rat

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

Background: Zinc finger and BTB domain-containing protein 7A (LRF, Pokemon, FBI1) is a transcriptional repressor encoded by the ZBTB7A gene that belongs to the POK (POZ and Kruppel)/ZBTB (zinc finger and BTB) family (1). LRF is broadly expressed with elevated expression in a variety of cancers relative to normal tissues, including non-small cell lung cancer, breast cancer, ovarian cancer, prostate cancer, and hepatocellular carcinoma (1-8). Research studies suggest that LRF acts as an oncogene through various mechanisms including repression of the tumor suppressors ARF and Rb, and repression of the cell cycle arrest factor p21Cip1 (9-11). The LRF transcription factor plays key roles during several stages of hematopoiesis including promoting lymphoid progenitor cells to commit to B cell differentiation by repressing T cell-promoting Notch signals, and promoting cell survival during terminal erythroid differentiation through suppression of the proapoptotic factor Bim (12,13).

$305
50 tests
100 µl
This Cell Signaling Technology antibody is conjugated to phycoerythrin (PE) 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 HDAC6 (D2E5) Rabbit mAb #7558.
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Flow Cytometry

Background: HDAC6 is a class II histone deacetylase enzyme localized to the cytoplasm and associated with the microtubule network (1). It is involved in the regulation of many cellular processes, including cell migration, immune synapse formation, viral infection, and degradation of misfolded proteins (1). HDAC6 contains two tandem catalytic domains that facilitate the deacetylation of multiple protein substrates, including histones and non-histone proteins such as tubulin, cortactin, and HSP90. Despite the ability to deacetylate histone proteins in vitro, there is no evidence for HDAC6-mediated deacetylation of histones in vivo (2,3). The acetylation/deacetylation of tubulin on Lys40 regulates binding and motility of the kinesin-1 motor protein and subsequent transport of cargo proteins such as JNK-interacting protein 1 (JIP1) (4). The acetylation/deacetylation of cortactin regulates cell motility by modulating the binding of cortactin to F-actin (5). Acetylation/deacetylation of HSP90 modulates chaperone complex activity by regulating the binding of an essential cochaperone protein, p23 (6,7). In addition to its role as a protein deacetylase, HDAC6 functions as a component of the aggresome, a proteinaceous inclusion body that forms in response to an accumulation of misfolded or partially denatured proteins (8). Formation of the aggresome is a protective response that sequesters cytotoxic protein aggregates for eventual autophagic clearance from the cell. HDAC6 contains a zinc finger ubiquitin-binding domain that binds both mono- and poly-ubiquitinated proteins (8). HDAC6 binds to both poly-ubiquitinated misfolded proteins and dynein motors, facilitating the transport of misfolded proteins to the aggresome (9,10). HDAC6 is also required for subsequent recruitment of the autophagic machinery and clearance of aggresomes from the cell (11). Thus, HDAC6 plays a key role in the protection against the deleterious effects of pathological protein aggregation that occurs in various diseases, such as neurodegenerative Huntington’s disease (11).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Flow Cytometry, Immunoprecipitation, Western Blotting

Background: The transcription factor Th-inducing POZ/Krüppel-like factor (ThPOK, ZBTB7B, cKROX, ZFP67) is a transcriptional repressor belonging to the POK/ZBTB family of lymphoid cell development regulators (1). ThPOK is best known as a signature CD4+ Th cell transcription factor that is upregulated during the differentiation of CD4+ Th but not CD8+ cytotoxic T cells (1). Expression of ThPOK in developing T cells represses expression of CD8 and cytotoxic T cell effector genes, and indirectly promotes expression of CD4 by antagonizing RUNX-mediated CD4 repression (2-4). ThPOK expression has also been observed in NKT cells and γδ T cells (5,6).

$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. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated EGR1 (44D5) Rabbit mAb #4154.
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Flow Cytometry

Background: EGR family members are transcriptional factors that contain three repetitive zinc finger DNA binding domains which bind to EGR response elements (ER) to regulate target gene expression (1). The expression of EGR family members is induced by growth factors, with EGR1 expression being induced by NGF (1,2). Increased EGR1 expression activates transcription of other signaling molecules, including CDK5 and tyrosine hydroxylase, and exerts long term effects on neural cell growth and differentiation (2,3).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

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

Background: ETS-related gene (ERG) is a member of the E-26 transformation-specific (ETS) family of sequence-specific DNA-binding transcription factors (1). ERG plays important and highly conserved roles in vertebrate development. Early in embryonic development, ERG is highly expressed in the embryonic mesoderm and endothelium, where it plays a critical role in the formation of the vascular system, urogenital tract and bone development (2,3). Later in embryonic development, ERG functions to regulate the pluripotency of hematopoietic stem cells, endothelial cell homeostasis and angiogenesis (2,4-7). ERG expression is not restricted to development. In adult mouse, ERG is normally expressed in endothelial tissues, including adrenal, cartilage, heart, spleen, lymphatic endothelial and eosinophil cells (8). However, deregulation of ERG activity, often resulting from chromosomal rearrangements, has been implicated and linked to poor prognosis in a number of different cancers. Chromosomal translocations generating EWS/ERG chimeric proteins comprised of the amino-terminal transactivation domain of Ewing’s sarcoma breakpoint region 1 (EWS) and the carboxy-terminal ETS domain of ERG have been identified in 5-10% of Ewing’s sarcoma, an aggressive bone and soft tissue tumor (9). Chromosomal translocations between ERG and TLS/FUS or ERG and ELF4 have been implicated in acute myeloid leukemia (10, 11). Over-expression of ERG, resulting from gene fusion with the androgen-driven promoter of the TMPRSS2 gene, has been identified as a key driver of metastasis and marker for poor prognosis in prostate cancer (12).

$303
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

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

Background: Sequestosome 1 (SQSTM1, p62) is a ubiquitin binding protein involved in cell signaling, oxidative stress, and autophagy (1-4). It was first identified as a protein that binds to the SH2 domain of p56Lck (5) and independently found to interact with PKCζ (6,7). SQSTM1 was subsequently found to interact with ubiquitin, providing a scaffold for several signaling proteins and triggering degradation of proteins through the proteasome or lysosome (8). Interaction between SQSTM1 and TRAF6 leads to the K63-linked polyubiquitination of TRAF6 and subsequent activation of the NF-κB pathway (9). Protein aggregates formed by SQSTM1 can be degraded by the autophagosome (4,10,11). SQSTM1 binds autophagosomal membrane protein LC3/Atg8, bringing SQSTM1-containing protein aggregates to the autophagosome (12). Lysosomal degradation of autophagosomes leads to a decrease in SQSTM1 levels during autophagy; conversely, autophagy inhibitors stabilize SQSTM1 levels. Studies have demonstrated a link between SQSTM1 and oxidative stress. SQSTM1 interacts with KEAP1, which is a cytoplasmic inhibitor of NRF2, a key transcription factor involved in cellular responses to oxidative stress (3). Thus, accumulation of SQSTM1 can lead to an increase in NRF2 activity.

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Chromatin IP, Chromatin IP-seq, Flow Cytometry, Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting

Background: Specificity protein 1 (SP1) is a ubiquitously expressed transcription factor belonging to the family of C2H2-type zinc finger containing DNA-binding proteins. SP1 binds GC-rich motifs with high affinity and regulates the expression of numerous mammalian genes (1,2). It interacts with many other transcription factors, such as c-Myc, EGR1, and Stat1, and with basal transcription machinery components. SP1 interacts with chromatin-modifying factors, such as histone deacetylases (HDACs) and p300 in chromatin remodeling. Transcriptional activity and stability of SP1 are regulated by post-translational modification, including phosphorylation, acetylation, ubiquitination, and glycosylation (3). Glycosylation of SP1 following insulin treatment leads to increased nuclear localization, while glucagon treatment increases cytoplasmic SP1 levels (4-6). Investigators have found high levels of SP1 in patients with Alzheimer's disease (7).

$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. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated ERG (A7L1G) Rabbit mAb #97249.
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Flow Cytometry

Background: ETS-related gene (ERG) is a member of the E-26 transformation-specific (ETS) family of sequence-specific DNA-binding transcription factors (1). ERG plays important and highly conserved roles in vertebrate development. Early in embryonic development, ERG is highly expressed in the embryonic mesoderm and endothelium, where it plays a critical role in the formation of the vascular system, urogenital tract and bone development (2,3). Later in embryonic development, ERG functions to regulate the pluripotency of hematopoietic stem cells, endothelial cell homeostasis and angiogenesis (2,4-7). ERG expression is not restricted to development. In adult mouse, ERG is normally expressed in endothelial tissues, including adrenal, cartilage, heart, spleen, lymphatic endothelial and eosinophil cells (8). However, deregulation of ERG activity, often resulting from chromosomal rearrangements, has been implicated and linked to poor prognosis in a number of different cancers. Chromosomal translocations generating EWS/ERG chimeric proteins comprised of the amino-terminal transactivation domain of Ewing’s sarcoma breakpoint region 1 (EWS) and the carboxy-terminal ETS domain of ERG have been identified in 5-10% of Ewing’s sarcoma, an aggressive bone and soft tissue tumor (9). Chromosomal translocations between ERG and TLS/FUS or ERG and ELF4 have been implicated in acute myeloid leukemia (10, 11). Over-expression of ERG, resulting from gene fusion with the androgen-driven promoter of the TMPRSS2 gene, has been identified as a key driver of metastasis and marker for poor prognosis in prostate cancer (12).

$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. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated SP1 (D4C3) Rabbit mAb #9389.
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Flow Cytometry

Background: Specificity protein 1 (SP1) is a ubiquitously expressed transcription factor belonging to the family of C2H2-type zinc finger containing DNA-binding proteins. SP1 binds GC-rich motifs with high affinity and regulates the expression of numerous mammalian genes (1,2). It interacts with many other transcription factors, such as c-Myc, EGR1, and Stat1, and with basal transcription machinery components. SP1 interacts with chromatin-modifying factors, such as histone deacetylases (HDACs) and p300 in chromatin remodeling. Transcriptional activity and stability of SP1 are regulated by post-translational modification, including phosphorylation, acetylation, ubiquitination, and glycosylation (3). Glycosylation of SP1 following insulin treatment leads to increased nuclear localization, while glucagon treatment increases cytoplasmic SP1 levels (4-6). Investigators have found high levels of SP1 in patients with Alzheimer's disease (7).

$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. This antibody is expected to exhibit the same species cross-reactivity as the unconjugated PU.1 (9G7) Rabbit mAb #2258.
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Flow Cytometry

Background: PU.1 is a member of the Ets family of transcription factors and activates target genes through the purine-rich PU-box (1). PU.1 plays a pivotal role in the differentiation of myeloid cells and lymphocytes and is expressed in several hematopoietic cells including B lymphocytes, macrophages, neutrophils, mast cells, early erythroid cells, and megakaryocytes (1,2). The concentration of PU.1 is critical for both the determination of hematopoietic cell lineage and the regulation of differentiation versus stem cell proliferation (3,4). In addition, PU.1 activity is influenced by phosphorylation and interactions with other hematopoietic transcription factors. Phosphorylation of PU.1 at Ser146 by CK2 promotes binding to IRF4 and synergistic activation through the immunoglobulin κ 3' enhancer (5). Treatment of pro-B cells with IL-3 leads to phosphorylation of PU.1 at Ser140, resulting in increased PU.1 activity and activation of the anti-apoptotic gene MCL-1 (6). GATA1 binding blocks PU.1 activity during erythroid cell development (7). Overexpression of PU.1 resulting from proviral insertion during Friend virus infection can induce erythroleukemia, while reduced expression has been associated with acute myeloid leukemia (8).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Monkey

Application Methods: Chromatin IP, Chromatin IP-seq, Flow Cytometry, Immunofluorescence (Immunocytochemistry), Immunoprecipitation, Western Blotting

Background: YY1 (Yin Yang1) is a ubiquitously expressed transcription factor with fundamental roles in embryogenesis, differentiation, replication and proliferation. YY1 contains four zinc finger motifs of the Cys-Cys-His-His type and can activate different eukaryotic genes (such as CREB, c-myc, Histone H4, p53 and PARP-1) or repress different eukaryotic genes (such as α-actin, IFN-β and IFN-γ) as well as regulate some viral promoters (1). YY1 deficient embryos die approximately at the time of implantation, suggesting that YY1 has an essential role in embryonic development (2). YY1 is overexpressed in cancer cells such as prostate cancer and therefore may be considered a prognostic marker (1).

$305
50 tests
100 µl
This Cell Signaling Technology antibody is conjugated to phycoerythrin (PE) 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 CHOP (L63F7) Mouse mAb #2895.
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Flow Cytometry

Background: CHOP was identified as a C/EBP-homologous protein that inhibits C/EBP and LAP in a dominant-negative manner (1). CHOP expression is induced by certain cellular stresses including starvation and the induced CHOP suppresses cell cycle progression from G1 to S phase (2). Later it was shown that, during ER stress, the level of CHOP expression is elevated and CHOP functions to mediate programmed cell death (3). Studies also found that CHOP mediates the activation of GADD34 and Ero1-Lα expression during ER stress. GADD34 in turn dephosphorylates phospho-Ser51 of eIF2α thereby stimulating protein synthesis. Ero1-Lα promotes oxidative stress inside the endoplasmic reticulum (ER) (4). The role of CHOP in the programmed cell death of ER-stressed cells is correlated with its role promoting protein synthesis and oxidative stress inside the ER (4).

$129
100 µg
This Cell Signaling Technology antibody is conjugated to PE and tested in-house for direct flow cytometric analysis in mouse cells.
APPLICATIONS
REACTIVITY
Mouse

Application Methods: Flow Cytometry

Background: IFN-γ plays key roles in both the innate and adaptive immune response. IFN-γ activates the cytotoxic activity of innate immune cells, such as macrophages and NK cells (1,2). IFN-γ production by NK cells and antigen presenting cells (APCs) promotes cell-mediated adaptive immunity by inducing IFN-γ production by T lymphocytes, increasing class I and class II MHC expression, and enhancing peptide antigen presentation (1). The anti-viral activity of IFN-γ is due to its induction of PKR and other regulatory proteins. Binding of IFN-γ to the IFNGR1/IFNGR2 complex promotes dimerization of the receptor complexes to form the (IFNGR1/IFNGR2)2 -IFN-γ dimer. Binding induces a conformational change in receptor intracellular domains and signaling involves Jak1, Jak2, and Stat1 (3). The critical role of IFN-γ in amplification of immune surveillance and function is supported by increased susceptibility to pathogen infection by IFN-γ or IFNGR knockout mice and in humans with inactivating mutations in IFNGR1 or IFNGR2. IFN-γ also appears to have a role in atherosclerosis (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 analysis of human cells. The unconjugated antibody #2258 reacts with human and mouse PU.1 protein. CST expects that PU.1 (9G7) Rabbit mAb (Alexa Fluor® 488 Conjugate) will also recognize PU.1 in these species.
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Flow Cytometry

Background: PU.1 is a member of the Ets family of transcription factors and activates target genes through the purine-rich PU-box (1). PU.1 plays a pivotal role in the differentiation of myeloid cells and lymphocytes and is expressed in several hematopoietic cells including B lymphocytes, macrophages, neutrophils, mast cells, early erythroid cells, and megakaryocytes (1,2). The concentration of PU.1 is critical for both the determination of hematopoietic cell lineage and the regulation of differentiation versus stem cell proliferation (3,4). In addition, PU.1 activity is influenced by phosphorylation and interactions with other hematopoietic transcription factors. Phosphorylation of PU.1 at Ser146 by CK2 promotes binding to IRF4 and synergistic activation through the immunoglobulin κ 3' enhancer (5). Treatment of pro-B cells with IL-3 leads to phosphorylation of PU.1 at Ser140, resulting in increased PU.1 activity and activation of the anti-apoptotic gene MCL-1 (6). GATA1 binding blocks PU.1 activity during erythroid cell development (7). Overexpression of PU.1 resulting from proviral insertion during Friend virus infection can induce erythroleukemia, while reduced expression has been associated with acute myeloid leukemia (8).

$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 of human cells. The unconjugated antibody #2258 reacts with human and mouse PU.1 protein. CST expects that PU.1 (9G7) Rabbit mAb (Alexa Fluor® 647 Conjugate) will also recognize PU.1 in these species.
APPLICATIONS
REACTIVITY
Human, Mouse

Application Methods: Flow Cytometry

Background: PU.1 is a member of the Ets family of transcription factors and activates target genes through the purine-rich PU-box (1). PU.1 plays a pivotal role in the differentiation of myeloid cells and lymphocytes and is expressed in several hematopoietic cells including B lymphocytes, macrophages, neutrophils, mast cells, early erythroid cells, and megakaryocytes (1,2). The concentration of PU.1 is critical for both the determination of hematopoietic cell lineage and the regulation of differentiation versus stem cell proliferation (3,4). In addition, PU.1 activity is influenced by phosphorylation and interactions with other hematopoietic transcription factors. Phosphorylation of PU.1 at Ser146 by CK2 promotes binding to IRF4 and synergistic activation through the immunoglobulin κ 3' enhancer (5). Treatment of pro-B cells with IL-3 leads to phosphorylation of PU.1 at Ser140, resulting in increased PU.1 activity and activation of the anti-apoptotic gene MCL-1 (6). GATA1 binding blocks PU.1 activity during erythroid cell development (7). Overexpression of PU.1 resulting from proviral insertion during Friend virus infection can induce erythroleukemia, while reduced expression has been associated with acute myeloid leukemia (8).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse

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

Background: PU.1 is a member of the Ets family of transcription factors and activates target genes through the purine-rich PU-box (1). PU.1 plays a pivotal role in the differentiation of myeloid cells and lymphocytes and is expressed in several hematopoietic cells including B lymphocytes, macrophages, neutrophils, mast cells, early erythroid cells, and megakaryocytes (1,2). The concentration of PU.1 is critical for both the determination of hematopoietic cell lineage and the regulation of differentiation versus stem cell proliferation (3,4). In addition, PU.1 activity is influenced by phosphorylation and interactions with other hematopoietic transcription factors. Phosphorylation of PU.1 at Ser146 by CK2 promotes binding to IRF4 and synergistic activation through the immunoglobulin κ 3' enhancer (5). Treatment of pro-B cells with IL-3 leads to phosphorylation of PU.1 at Ser140, resulting in increased PU.1 activity and activation of the anti-apoptotic gene MCL-1 (6). GATA1 binding blocks PU.1 activity during erythroid cell development (7). Overexpression of PU.1 resulting from proviral insertion during Friend virus infection can induce erythroleukemia, while reduced expression has been associated with acute myeloid leukemia (8).

$260
100 µl
APPLICATIONS
REACTIVITY
Human, Mouse, Rat

Application Methods: Chromatin IP, Chromatin IP-seq, Flow Cytometry, Immunofluorescence (Immunocytochemistry), Immunoprecipitation, Western Blotting

Background: EGR family members are transcriptional factors that contain three repetitive zinc finger DNA binding domains which bind to EGR response elements (ER) to regulate target gene expression (1). The expression of EGR family members is induced by growth factors, with EGR1 expression being induced by NGF (1,2). Increased EGR1 expression activates transcription of other signaling molecules, including CDK5 and tyrosine hydroxylase, and exerts long term effects on neural cell growth and differentiation (2,3).

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

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

Background: AML1 (also known as Runx1, CBFA2, and PEBP2αB) is a member of the core binding factor (CBF) family of transcription factors (1,2). It is required for normal development of all hematopoietic lineages (3-5). AML1 forms a heterodimeric DNA binding complex with its partner protein CBFβ and regulates the expression of cellular genes by binding to promoter and enhancer elements. AML1 is commonly translocated in hematopoietic cancers: chromosomal translocations include t(8;21) AML1-ETO, t(12;21) TEL-AML, and t(8;21) AML-M2 (6). Phosphorylation of AML1 on several potential serine and threonine sites, including Ser249, is thought to occur in an Erk-dependent manner (7,8).

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

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

Background: CREB is a bZIP transcription factor that activates target genes through cAMP response elements. CREB is able to mediate signals from numerous physiological stimuli, resulting in regulation of a broad array of cellular responses. While CREB is expressed in numerous tissues, it plays a large regulatory role in the nervous system. CREB is believed to play a key role in promoting neuronal survival, precursor proliferation, neurite outgrowth, and neuronal differentiation in certain neuronal populations (1-3). Additionally, CREB signaling is involved in learning and memory in several organisms (4-6). CREB is able to selectively activate numerous downstream genes through interactions with different dimerization partners. CREB is activated by phosphorylation at Ser133 by various signaling pathways including Erk, Ca2+, and stress signaling. Some of the kinases involved in phosphorylating CREB at Ser133 are p90RSK, MSK, CaMKIV, and MAPKAPK-2 (7-9).