Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P05412 (c-Jun)
 11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phosphorylation on serines or threonines preceding proline (Ser/Thr-Pro) is a major signaling mechanism. The conformation of a subset of phosphorylated Ser/Thr-Pro motifs is regulated by the prolyl isomerase Pin1. Inhibition of Pin1 induces apoptosis and may also contribute to neuronal death in Alzheimer's disease. However, little is known about the role of Pin1 in cancer or in modulating transcription factor activity. Here we report that Pin1 is strikingly overexpressed in human breast cancers, and that its levels correlate with cyclin D1 levels in tumors. Overexpression of Pin1 increases cellular cyclin D1 protein and activates its promoter. Furthermore, Pin1 binds c-Jun that is phosphorylated on Ser63/73-Pro motifs by activated JNK or oncogenic Ras. Moreover, Pin1 cooperates with either activated Ras or JNK to increase transcriptional activity of c-Jun towards the cyclin D1 promoter. Thus, Pin1 is up-regulated in human tumors and cooperates with Ras signaling in increasing c-Jun transcriptional activity towards cyclin D1. Given the crucial roles of Ras signaling and cyclin D1 overexpression in oncogenesis, our results suggest that overexpression of Pin1 may promote tumor growth.
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PMID:Pin1 is overexpressed in breast cancer and cooperates with Ras signaling in increasing the transcriptional activity of c-Jun towards cyclin D1. 1143 33

Phosphorylation of serine or threonine residue preceding proline (Ser/Thr-Pro) is a key regulatory mechanism. The conformation of certain phosphorylated Ser/Thr-Pro bonds is regulated specifically by the prolyl isomerase Pin1. Inhibition of Pin1 induces apoptosis and may contribute to neuronal death in Alzheimer's disease. It has been reported that Pin1 is strikingly overexpressed in a subset of human tumors. The differential display screen revealed that Pin1 increases the transcription of several target genes, including cyclin D1 and c-myc genes. Pin1 cooperates with Ras signaling in increasing the transcriptional activity of c-Jun towards cyclin D1. Pin1 also regulates turnover and subcellular localization of beta-catenin by inhibiting its interaction with adenomatous polyposis coli protein (APC). However, the analysis of Pin1 expression has not been demonstrated in human oral squamous cell carcinoma (OSCC). We examined the expression of Pin1 mRNA and protein in OSCC cell lines, and analyzed Pin1/cyclin D1/beta-catenin expression in OSCC clinical samples by immunohistochemical staining. We report that Pin1 is overexpressed in OSCC and its level correlates with cyclin D1 level. These results indicate that Pin1 is related to oncogenesis of OSCC.
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PMID:Pin1 is overexpressed in oral squamous cell carcinoma and its levels correlate with cyclin D1 overexpression. 1257 89

Phosphorylation on serine or threonine residue preceding proline (Ser/Thr-Pro) is a key regulatory mechanism. The conformation of certain phosphorylated Ser/Thr-Pro bonds is regulated specifically by the prolyl isomerase Pin1. It has been reported that Pin1 is strikingly overexpressed in a subset of human tumors. A differential-display screen reveals that Pin1 increases the transcription of several beta-catenin target genes, including those encoding cyclin D1 and c-Myc. Pin1 cooperates with Ras signaling in increasing the transcriptional activity of c-Jun towards cyclin D1. We have previously reported that Pin1 is overexpressed in oral squamous cell carcinoma (OSCC) and its level correlates with Cyclin D1 expression. However, the analysis of the relationship between Pin1 and other cyclin genes has not been demonstrated in human OSCC. We examined Pin1 mRNA and protein expressions in OSCC cell lines, and analyzed Pin1/cyclins expression by RT-PCR. We report that Pin1 mRNA correlates with Cyclin D1 mRNA expression and the expression of many cyclin genes is associated with lymph node metastasis in OSCC. These results indicate that Pin1 is a regulator of Cyclin D1 expression in OSCC and might have a role in oncogenesis; and the expression of many cyclin genes will be an indicator of lymph node metastasis in OSCC.
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PMID:Expression status of Pin1 and cyclins in oral squamous cell carcinoma: Pin1 correlates with Cyclin D1 mRNA expression and clinical significance of cyclins. 1279 68

The activation of the activating protein-1 (AP-1) family of transcription factors, including c-Fos and c-Jun family members, is one of the earliest nuclear events induced by growth factors that stimulate extracellular signal-regulated kinases (ERKs). In the case of c-Fos, the activation of ERK leads to an increased expression of c-fos mRNA. In turn, we have recently shown that ERK phosphorylates multiple residues within the carboxylterminal transactivation domain (TAD) of c-Fos, thus resulting in its increased transcriptional activity. However, how ERK-dependent phosphorylation regulates c-Fos function is still poorly understood. In this regard, it has been recently observed that the prolyl isomerase Pin1 can interact with proteins phosphorylated on serine or threonine residues that precede prolines (pS/T-P), such as the transcription factors p53 and c-Jun, thereby controlling their activity by promoting the cis-trans isomerization of these pS/T-P bonds. Here, we found that Pin1 binds c-Fos through specific pS/T-P sites within the c-Fos TAD, and that this interaction results in an enhanced transcriptional response of c-Fos to polypeptide growth factors that stimulate ERK. Our findings suggest that c-Fos represents a novel target for the isomerizing activity of Pin1 and support a role for Pin1 in the mechanism by which c-Jun and c-Fos can cooperate to regulate AP-1-dependent gene transcription upon phosphorylation by mitogen-activated kinase (MAPK) family members.
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PMID:Regulation of the transcriptional activity of c-Fos by ERK. A novel role for the prolyl isomerase PIN1. 1612 44

The peptidyl prolyl cis/trans isomerase Pin1 specifically binds phosphorylated Ser/Thr-Pro protein motifs and catalyzes the cis/trans isomerization of the peptide bond. Accumulating studies have revealed that Pin1 isomerase activity is regulated by its post-translational modifications, including phosphorylation and oxidation. Various transcription factors and regulators have been identified as substrates for Pin1. It enhances AP-1 activity via isomerization of both c-Jun and c-Fos for cellular proliferation and stabilizes the oncosuppressors p53 and p73 against DNA damage at the checkpoint. We demonstrated the association between the intracellular form of Notch1 (NIC) and Pin1 by analyzing Pin1/p53 double-knockout mice. Pin1 also regulates the post-transcriptional level of some cytokines, associated with asthma, that possess 3' untranslated region AU-rich elements (AREs) via interaction withAUF1, the nucleoprotein in the ARE-binding complex. Pin1 has been identified as the molecular partner of tau and amyloid precursor protein (APP), the key factors of Alzheimer's disease (AD). It interacts with the phosphorylated Thr-231 of tau and regulates its activity to bind microtubules. It further interacts with the phosphorylated Thr-668 of APP and affects its metabolism. Thus, Pin1 is probably involved in the pathogenesis of human diseases, including cancer, asthma, and AD, presenting an attractive target for future therapeutical drugs.
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PMID:Prolyl isomerase, Pin1: new findings of post-translational modifications and physiological substrates in cancer, asthma and Alzheimer's disease. 1796 33

Developing neurons deprived of trophic support undergo apoptosis mediated by activation of c-Jun N-terminal kinases (JNK) and c-Jun, induction of the Bcl-2 homology 3-only protein Bim(EL), Bax-dependent loss of mitochondrial cytochrome c, and caspase activation. However, the mechanisms that regulate each of these events are only partially understood. Here we show that the prolyl isomerase Pin1 functions as a positive regulator of neuronal death through a c-Jun-dependent mechanism. Ectopic Pin1 promoted caspase-dependent death of NGF-maintained neurons that was associated with an accumulation of Ser(63)-phosphorylated c-Jun in neuronal nuclei and was partially dependent on Bax. Downregulating Pin1 prior to NGF withdrawal suppressed the accumulation of phosphorylated c-Jun, inhibited the release of cytochrome c, and significantly delayed cell death. Pin1 knockdown inhibited NGF deprivation-induced death to a similar extent in Bim (+/+) and Bim (-/-) neurons. The protective effect of Pin1 knockdown was significantly greater than that caused by loss of Bim and nearly identical to that caused by a dominant negative form of c-Jun. Finally, cell death induced by ectopic Pin1 was largely blocked by expression of dominant negative c-Jun. These results suggest a novel mechanism by which Pin1 promotes cell death involving activation of c-Jun.
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PMID:Pin1 promotes cell death in NGF-dependent neurons through a mechanism requiring c-Jun activity. 1841 64

Acquired resistance to tamoxifen (TAM) is a serious therapeutic problem in breast cancer patients. Here, we found that TAM-resistant MCF-7 cells (TAMR-MCF-7 cells) produced higher levels of vascular endothelial growth factor (VEGF) than control MCF-7 cells. Molecular analyses using reporter genes and Western blots supported the involvement of c-Jun/activator protein-1 and hypoxia-inducible factor 1alpha in enhanced VEGF transcription in TAMR-MCF-7 cells. Pin1, a peptidyl prolyl isomerase, was consistently overexpressed in TAMR-MCF-7 cells, and c-Jun/activator protein-1-dependent VEGF transcription in TAMR-MCF-7 cells was almost completely inhibited by Pin1 siRNA and by the Pin1 inhibitor juglone. Chick chorioallantoic membrane assays confirmed that the increased angiogenic intensity of TAMR-MCF-7 cells was significantly suppressed by Pin1 inhibition. These results show that Pin1 overexpression is closely associated with VEGF-mediated angiogenesis and suggest that Pin1 is a potential therapeutic target of excessive angiogenesis in TAM-resistant breast cancer cases.
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PMID:Enhancement of vascular endothelial growth factor-mediated angiogenesis in tamoxifen-resistant breast cancer cells: role of Pin1 overexpression. 1967 42

Pin1 specifically catalyzes the cis/trans isomerization of phospho-Ser/Thr-Pro bonds and plays an important role in many cellular events through the effects of conformational change on the function of its biological substrates, including cell division cycle 25 C (Cdc25C), c-Jun and p53. Pin1 is overexpressed in many human cancer tissues, including breast, prostate and lung cancer. Its expression correlates with cyclin D1 levels, which contribute to cell transformation. Overexpression of Pin1 promotes tumor growth, while inhibition of Pin1 causes tumor cell apoptosis. Pin1 plays an important role in oncogenesis and therefore may serve as an effective anticancer target. Many inhibitors of Pin1 have been discovered, including several classes of designed inhibitors (alkene isosteres, reduced amides, indanyl ketones) and natural products (juglone, pepticinnamin E analogues, PiB and its derivatives obtained from a library screen). Pin1 inhibitors could be used as a novel type of anticancer drug by blocking cell cycle progression. Therefore, Pin1 represents a new diagnostic and therapeutic anticancer drug target.
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PMID:Pin1 as an anticancer drug target. 1989 Apr 97

In normal neurons, neurofilament (NF) proteins are phosphorylated in the axonal compartment. However, in neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), NF proteins are aberrantly hyperphosphorylated within the cell bodies. The aberrant hyperphosphorylation of NF accumulations found in neurodegeneration could be attributable to either deregulation of proline-directed Ser/Thr kinase(s) activity or downregulation of protein phosphatase(s) activity. In this study, we found that protein phosphatase 2A (PP2A) expression is high in neuronal cell bodies and that inhibition of PP2A activity by okadaic acid (OA), microcystin LR (mLR), or fostriecin (Fos) leads to perikaryal hyperphosphorylation of NF. Peptidyl-prolyl isomerase Pin1 inhibits the dephosphorylation of NF by PP2A in vitro. In cortical neurons, Pin1 modulates the topographic phosphorylation of the proline-directed Ser/Thr residues within the tail domain of NF proteins by inhibiting the dephosphorylation by PP2A. Inhibition of Pin1 inhibits OA-induced aberrant perikaryal phosphorylation of NF. Treatment of cortical neurons with OA or Fos prevents the general anterograde transport of transfected green fluorescent protein-high-molecular-mass (NF-H) into axons caused by hyperphosphorylation of NF-H, and inhibition of Pin1 rescues this effect. Furthermore, inhibition of Pin1 inhibits the OA- or Fos-induced neuronal apoptosis. We show that OA-induced hyperphosphorylation of NF is a consequence of dephosphorylation of NF and is independent of c-Jun N-terminal protein kinase, extracellular signal-regulated kinase, and cyclin-dependent kinase-5 pathways. This study highlights a novel signaling role of PP2A by Pin1 and implicates Pin1 as a therapeutic target to reduce aberrant phosphorylation of NF proteins in neurodegenerative disorders such as AD, PD, and ALS.
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PMID:Peptidyl-prolyl isomerase 1 regulates protein phosphatase 2A-mediated topographic phosphorylation of neurofilament proteins. 1994 Jan 83

Pin1 [Protein Interacting with NIMA (never in mitosis A)] is a peptidyl prolyl cis-trans isomerase that isomerizes phospho-Serine/Threonine-Proline [p(S/T)-P] motifs of its target proteins. Pin1 functions in concert with proline directed kinases such as cyclin-dependent protein kinases, extracellular signal-regulated kinases, and c-Jun N- terminal kinase, and protein phosphatases such as protein phosphatase 2A (PP2A) and PP2B, in the regulation of a wide range of cellular processes including cell division, DNA damage response, and gene transcription, and in susceptibility to cancer and neurodegenerative diseases. This review focuses on the roles of Pin1 in neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Frontotemporal dementia associated with parkinsonism linked to chromosome 17. Pin1 interacts with neuronal cytoskeletal proteins such as tau, amyloid-beta protein precursor, alpha-synuclein, and neurofilaments, often in association with phosphorylation events that influence their functions in the neuronal cytoskeleton. Overexpression of Pin1 reduces WT tau stability but increases P301L mutant tau stability. Pin1 associates with neurofilament H (NF-H) and modulates excitotoxic and oxidative stress induced perikaryal phosphorylation of NF-H. Pin1 mediates the neural specific apoptosis machinery. The specific inhibitors of Pin1 may have potential therapeutic implications in neurodegeneration.
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PMID:Phosphorylation-specific peptidyl-prolyl isomerization of neuronal cytoskeletal proteins by Pin1: implications for therapeutics in neurodegeneration. 2011 May 89


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