scholarly journals Modulation of β-Catenin Phosphorylation/Degradation by Cyclin-dependent Kinase 2

2004 ◽  
Vol 279 (19) ◽  
pp. 19592-19599 ◽  
Author(s):  
Chun Shik Park ◽  
Sung Il Kim ◽  
Mi Su Lee ◽  
Cho-ya Youn ◽  
Dae Joong Kim ◽  
...  
Keyword(s):  
Cyclin E ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Cyclin Dependent Kinase ◽  
Rapid Degradation ◽  
Subsequent Degradation ◽  
Proteasome Pathway ◽  
Fine Tune

β-Catenin functions as a downstream component of the Wnt/Wingless signal transduction pathway, and inappropriate control of cytosolic β-catenin is a crucial step in the genesis of several human cancers. Here we demonstrate that cyclin-dependent kinase 2 (CDK2) in association with cyclin A or cyclin E directly binds to β-catenin.In vivoandin vitrokinase assays with cyclin-CDK2 demonstrate β-catenin phosphorylation on residues Ser33, Ser37, Thr41, and Ser45. This phosphorylation promotes rapid degradation of cytosolic β-catenin via the β-TrCP-mediated proteasome pathway. Moreover, cyclin E-CDK2 contributes to rapid degradation of cytosolic β-catenin levels during G1phase by regulating β-catenin phosphorylation and subsequent degradation. In this way, CDK2 may “fine tune” β-catenin levels over the course of the cell cycle.

Novel pathway for thyroid hormone receptor action through interaction with jun and fos oncogene activities

1991 ◽  
Vol 11 (12) ◽  
pp. 6016-6025
Author(s):  
X K Zhang ◽  
K N Wills ◽  
M Husmann ◽  
T Hermann ◽  
M Pfahl
Keyword(s):  
Signal Transduction ◽  
Dna Binding ◽  
Thyroid Hormone Receptor ◽  
Gene Activation ◽  
Signal Transduction Pathway ◽  
Large Family ◽  
Transduction Pathway ◽  
Regulatory Pathway

Many essential biological pathways, including cell growth, development, and metabolism, are regulated by thyroid hormones (THs). TH action is mediated by intracellular receptors that belong to a large family of ligand-dependent transcription factors, including the steroid hormone and retinoic acid receptors. So far it has been assumed that TH receptors (TRs) regulate gene transcription only through the classical protein-DNA interaction mechanism. Here we provide evidence for a regulatory pathway that allows cross-talk between TRs and the signal transduction pathway used by many growth factors, oncogenes, and tumor promoters. In transient transfection studies, we observed that the oncogenes c-jun and c-fos inhibit TR activities, while TRs inhibit induction of the c-fos promoter and repress AP-1 site-dependent gene activation. A truncated TR that lacks only 17 amino acids from the carboxy terminus can no longer antagonize AP-1 activity. The cross-regulation between TRs and the signal transduction pathway appears to be based on the ability of TRs to inhibit DNA binding of the transcription factor AP-1 in the presence of THs. The constituents of AP-1, c-Jun, and c-Fos, vice versa, can inhibit TR-induced gene activation in vivo, and c-Jun inhibits TR DNA binding in vitro. This novel regulatory pathway is likely to play a major role in growth control and differentiation by THs.

scholarly journals Erythropoietin-Induced Activation of STAT5 Is Impaired in the Myelodysplastic Syndrome

Blood ◽  
1997 ◽  
Vol 89 (5) ◽  
pp. 1690-1700 ◽  
Author(s):  
Lies H. Hoefsloot ◽  
Martine P. van Amelsvoort ◽  
Lianne C.A.M. Broeders ◽  
Dorien C. van der Plas ◽  
Kirsten van Lom ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Myelodysplastic Syndrome ◽  
Signal Transduction Pathway ◽  
Binding Activity ◽  
Signal Transducer ◽  
Transduction Pathway ◽  
Normal Bone ◽  
Marrow Cells

Abstract Patients with myelodysplastic syndrome (MDS) have ineffective in vivo and in vitro erythropoiesis, characterized by an impaired response to erythropoietin (Epo). We examined proliferation and maturation of MDS marrow cells in response to Epo in more detail. Epo-dependent DNA synthesis as well as induction of GATA-1 binding activity in marrow cells from 15 MDS cases were severely reduced as compared with normal bone marrow (NBM). Additionally, the appearance of morphologically identifiable erythroid cells was decreased in MDS cell cultures. These data indicate that both the Epo-dependent proliferation as well as the differentiation induction by Epo is suppressed. To study more upstream events of the Epo signal transduction route we investigated activation of the signal transducer and activator of transcription (STAT) 5. In all 15 MDS samples tested, STAT5 activation was absent or greatly suppressed in response to Epo. In contrast, interleukin-3 induced a normal STAT5 response in MDS cells. Further, in MDS the subset of CD71+ BM cells that is phenotypically similar to Epo-responsive cells in normal marrow, was present. We conclude that the Epo response in MDS is disturbed at an early point in the Epo receptor (EpoR) signal transduction pathway.

scholarly journals Phosphorylation of the myristoylated protein kinase C substrate MARCKS by the cyclin E–cyclin-dependent kinase 2 complex in vitro

1999 ◽  
Vol 340 (3) ◽  
pp. 775-782 ◽  
Author(s):  
Stéphane MANENTI ◽  
Emiko YAMAUCHI ◽  
Odile SOROKINE ◽  
Martine KNIBIEHLER ◽  
Alain VAN DORSSELAER ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cyclin E ◽  
Cyclin Dependent Kinase ◽  
Kinase Substrate ◽  
Cyclin Dependent Kinases ◽  
Kinase C ◽  
Cdk2 Complex

The myristoylated alanine-rich C-kinase substrate (MARCKS) purified from brain was recently characterized as a proline-directed kinase(s) substrate in vivo [Taniguchi, Manenti, Suzuki and Titani (1994) J. Biol. Chem. 269, 18299-18302]. Here we have investigated the phosphorylation of MARCKS by various cyclin-dependent kinases (Cdks) in vitro. We established that Cdk2, Cdk4 and, to a smaller extent, Cdk1 that have been immunoprecipitated from cellular extracts phosphorylate MARCKS. Comparison of MARCKS phosphorylation by protein kinase C (PKC) and by the purified cyclin E-Cdk2 complex suggested that two residues were phosphorylated by Cdk2 under these conditions. To identify these sites, Cdk2-phosphorylated MARCKS was digested with lysyl endoprotease and analysed by electrospray MS. Comparison with the digests obtained from the unphosphorylated protein demonstrated that two peptides, Gly12-Lys30 and Ala138-Lys152, were phosphorylated by cyclin E-Cdk2. The identity of these peptides was confirmed by automatic Edman degradation. On the basis of the consensus phosphorylation sequence described for Cdk2, and on MS/MS analysis of the Ala138-Lys152 peptide, we concluded that Ser27, one of the phosphorylation sites identified in vivo, and Thr150 were the Cdk2 targets in vitro. None of the other sites described in vivo were phosphorylated in these conditions. Interestingly, a preliminary phosphorylation of MARCKS by PKC improved the initial rate of phosphorylation by Cdk2 without modifying the number of sites concerned. In contrast, phosphorylation of MARCKS by Cdk2 did not significantly affect further phosphorylation by PKC.

scholarly journals Erythropoietin-Induced Activation of STAT5 Is Impaired in the Myelodysplastic Syndrome

Blood ◽  
1997 ◽  
Vol 89 (5) ◽  
pp. 1690-1700 ◽  
Author(s):  
Lies H. Hoefsloot ◽  
Martine P. van Amelsvoort ◽  
Lianne C.A.M. Broeders ◽  
Dorien C. van der Plas ◽  
Kirsten van Lom ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Myelodysplastic Syndrome ◽  
Signal Transduction Pathway ◽  
Binding Activity ◽  
Signal Transducer ◽  
Transduction Pathway ◽  
Normal Bone ◽  
Marrow Cells

Patients with myelodysplastic syndrome (MDS) have ineffective in vivo and in vitro erythropoiesis, characterized by an impaired response to erythropoietin (Epo). We examined proliferation and maturation of MDS marrow cells in response to Epo in more detail. Epo-dependent DNA synthesis as well as induction of GATA-1 binding activity in marrow cells from 15 MDS cases were severely reduced as compared with normal bone marrow (NBM). Additionally, the appearance of morphologically identifiable erythroid cells was decreased in MDS cell cultures. These data indicate that both the Epo-dependent proliferation as well as the differentiation induction by Epo is suppressed. To study more upstream events of the Epo signal transduction route we investigated activation of the signal transducer and activator of transcription (STAT) 5. In all 15 MDS samples tested, STAT5 activation was absent or greatly suppressed in response to Epo. In contrast, interleukin-3 induced a normal STAT5 response in MDS cells. Further, in MDS the subset of CD71+ BM cells that is phenotypically similar to Epo-responsive cells in normal marrow, was present. We conclude that the Epo response in MDS is disturbed at an early point in the Epo receptor (EpoR) signal transduction pathway.

scholarly journals Direct Binding of the Signal-transducing Adaptor Grb2 Facilitates Down-regulation of the Cyclin-dependent Kinase Inhibitor p27Kip1

2001 ◽  
Vol 276 (15) ◽  
pp. 12084-12090 ◽  
Author(s):  
Yoriko Sugiyama ◽  
Kiichiro Tomoda ◽  
Toshiaki Tanaka ◽  
Yukinobu Arata ◽  
Noriko Yoneda-Kato ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Kinase Inhibitor ◽  
Signal Sequence ◽  
Ectopic Expression ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Cyclin Dependent Kinase ◽  
Down Regulation ◽  
Cytoplasmic Transport ◽  
Subsequent Degradation

Ectopic expression of Jab1/CSN5 induces specific down-regulation of the cyclin-dependent kinase (Cdk) inhibitor p27 (p27Kip1) in a manner dependent upon transportation from the nucleus to the cytoplasm. Here we show that Grb2 and Grb3-3, the molecules functioning as an adaptor in the signal transduction pathway, specifically and directly bind to p27 in the cytoplasm and participate in the regulation of p27. The interaction requires the C-terminal SH3-domain of Grb2/3-3 and the proline-rich sequence contained in p27 immediately downstream of the Cdk binding domain. In living cells, enforcement of the cytoplasmic localization of p27, either by artificial manipulation of the nuclear/cytoplasmic transport signal sequence or by coexpression of ectopic Jab1/CSN5, markedly enhances the stable interaction between p27 and Grb2. Overexpression of Grb2 accelerates Jab1/CSN5-mediated degradation of p27, while Grb3-3 expression suppresses it. A p27 mutant unable to bind to Grb2 is transported into the cytoplasm in cells ectopically expressing Jab1/CSN5 but is refractory to the subsequent degradation. These findings indicate that Grb2 participates in a negative regulation of p27 and may directly link the signal transduction pathway with the cell cycle regulatory machinery.

The Suppression of Small GTPase Rho Signal Transduction Pathway Inhibits Angiogenesis in Vitro and in Vivo

2000 ◽  
Vol 269 (2) ◽  
pp. 633-640 ◽  
Author(s):  
Shigeki Uchida ◽  
Go Watanabe ◽  
Yutaka Shimada ◽  
Masato Maeda ◽  
Atsushi Kawabe ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Signal Transduction Pathway ◽  
Small Gtpase ◽  
Transduction Pathway

Induction of phosphoinositide-mediated signal transduction pathway by 17 beta-oestradiol in rat vaginal epithelial cells

1997 ◽  
Vol 19 (3) ◽  
pp. 249-257 ◽  
Author(s):  
S Singh ◽  
PD Gupta
Keyword(s):  
Signal Transduction ◽  
Epithelial Cells ◽  
Calcium Uptake ◽  
Inositol Phosphate ◽  
Primary Cultures ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Vaginal Epithelial Cells

In the present study, the induction of the phosphoinositide signal transduction pathway by 17 beta-oestradiol has been demonstrated in rat vaginal epithelial cells (VEC). We have shown an increase in the metabolism of phosphoinositol lipids by 3H-myoinositol incorporation as well as production of inositol phosphate in VEC in vivo and in vitro following oestradiol administration. Concomitant changes in intracellular calcium levels have also been observed under the influence of oestradiol. To rule out the effects of cytokines, parallel studies were performed using primary cultures of VEC. Oestradiol-induced calcium uptake was seen even in the presence of actinomycin D and cycloheximide which inhibit transcription and translation respectively. Calcium uptake was blocked by neomycin, an inhibitor of phosphoinositol lipid metabolism, and by the oestrogen receptor antagonist tamoxifen. Results suggest that oestradiol induces second messenger pathways in the VEC through specific receptors. Implications of these observations in cellular differentiation processes are discussed.

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