Phosphorylation by protein kinase CKII modulates the DNA-binding activity of a chloroplast nucleoid-associated protein

Planta ◽  
2004 ◽  
Vol 219 (2) ◽  
pp. 298-302 ◽  
Author(s):  
Nancy Peffer ◽  
Iris Meier ◽  
Sun Yong Jeong
Keyword(s):  
Protein Kinase ◽  
Dna Binding ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Protein Kinase Ckii ◽  
Chloroplast Nucleoid

scholarly journals Biphasic regulation of extracellular-signal-regulated protein kinase by leptin in macrophages: role in regulating STAT3 Ser727 phosphorylation and DNA binding

2002 ◽  
Vol 364 (3) ◽  
pp. 875-879 ◽  
Author(s):  
Lisa O'ROURKE ◽  
Peter R. SHEPHERD
Keyword(s):  
Protein Kinase ◽  
Dna Binding ◽  
Leptin Receptor ◽  
Binding Activity ◽  
Mitogen Activated Protein Kinase ◽  
Time Points ◽  
Dna Binding Activity ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Stat3 Phosphorylation

Activation of the transcription factor signal transducer and activator of transcription 3 (STAT3) requires dimerization that is induced by phosphorylation of Tyr705, but its activity can be further modulated by phosphorylation at Ser727 in a manner that is dependent on cell context and the stimulus used. The role of STAT3 Ser727 phosphorylation in leptin signalling is currently not known. While cells transfected with the signalling-competent long form of the leptin receptor (ObRb) have been used to study leptin signalling, these are likely to be of limited use in studying STAT3 Ser727 phosphorylation due to the importance of cell background in determining the nature of the response. However, we have recently found that J774.2 macrophages endogenously express high levels of ObRb, and using these cells we find that leptin stimulates STAT3 phosphorylation on both Tyr705 and Ser727. The phosphorylation of Ser727 was not affected by rapamycin or the protein kinase C inhibitor H7 [1-(5-isoquinolinylsulphonyl)-2-methylpiperazine dihydrochloride]. While the MEK-1 [mitogen-activated protein kinase (MAP kinase)/extracellular-signal-related kinase (ERK) kinase-1] inhibitor PD98059 [(2-amino-3′-methoxyphenyl)oxanaphthalen-4-one] had no effect on leptin-stimulated phosphorylation of STAT3 Tyr705, it greatly attenuated leptin's effects on STAT3 Ser727 phosphorylation. Further, Ob's effect on the DNA binding activity of STAT3 was also greatly reduced at all time points by PD98059. Leptin-induced ERK activation in J774.2 cells shows a biphasic pattern, with an initial reduction in ERK phosphorylation for up to 10min following leptin stimulation, while at later time points phosphorylation of ERK was increased above basal levels. The increase in ERK activity corresponded with an increase in both phosphorylation of Ser727 and STAT3 DNA binding activity. These data provide the first evidence that ERK-mediated phosphorylation of Ser727 is required for full stimulation of STAT3 by leptin.

scholarly journals Jun is phosphorylated by several protein kinases at the same sites that are modified in serum-stimulated fibroblasts.

1992 ◽  
Vol 12 (10) ◽  
pp. 4694-4705 ◽  
Author(s):  
S J Baker ◽  
T K Kerppola ◽  
D Luk ◽  
M T Vandenberg ◽  
D R Marshak ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Dna Binding ◽  
Glycogen Synthase ◽  
In Vitro Transcription ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Serum Stimulation ◽  
Dependent Protein

c-jun is a member of the family of immediate-early genes whose expression is induced by factors such as serum stimulation, phorbol ester, and differentiation signals. Here we show that increased Jun synthesis after serum stimulation is accompanied by a concomitant increase in phosphorylation. Several serine-threonine kinases were evaluated for their ability to phosphorylate Jun in vitro. p34cdc2, protein kinase C, casein kinase II, and pp44mapk phosphorylated Jun efficiently, whereas cyclic AMP-dependent protein kinase and glycogen synthase kinase III did not. The sites phosphorylated by p34cdc2 were similar to those phosphorylated in vivo after serum induction. The major sites of phosphorylation were mapped to serines 63, 73, and 246. Phosphorylation of full-length Jun with several kinases did not affect the DNA-binding activity of Jun homodimers or Fos-Jun heterodimers. Comparison of the DNA binding and in vitro transcription properties of wild-type and mutated proteins containing either alanine or aspartic acid residues in place of Ser-63, -73, and -246 revealed only minor differences among homodimeric complexes and no differences among Fos-Jun heterodimers. Thus, phosphorylation of Jun did not produce a significant change in dimerization, DNA-binding, or in vitro transcription activity. The regulatory role of phosphorylation in the modulation of Jun function is likely to be considerably more complex than previously suggested.

scholarly journals Signaling mechanisms regulating bombesin-mediated AP-1 gene induction in the human gastric cancer SIIA

2000 ◽  
Vol 279 (2) ◽  
pp. C326-C334 ◽  
Author(s):  
Hong Jin Kim ◽  
B. Mark Evers ◽  
David A. Litvak ◽  
Mark R. Hellmich ◽  
Courtney M. Townsend
Keyword(s):  
Gene Expression ◽  
Gastric Cancer ◽  
Protein Kinase ◽  
Dna Binding ◽  
Signaling Pathways ◽  
Binding Activity ◽  
Human Gastric Cancer ◽  
Rapid Induction ◽  
Dna Binding Activity ◽  
Jun B

The hormone bombesin (BBS) and its mammalian equivalent gastrin-releasing peptide (GRP) act through specific GRP receptors (GRP-R) to affect multiple cellular functions in the gastrointestinal tract; the intracellular signaling pathways leading to these effects are not clearly defined. Previously, we demonstrated that the human gastric cancer SIIA possesses GRP-R and that BBS stimulates activator protein-1 (AP-1) gene expression. The purpose of our present study was to determine the signaling pathways leading to AP-1 induction in SIIA cells. A rapid induction of c- jun and jun-B gene expression was noted after BBS treatment; this effect was blocked by specific GRP-R antagonists, indicating that BBS is acting through the GRP-R. The signaling pathways leading to increased AP-1 gene expression were delineated using phorbol 12-myristate 13-acetate (PMA), which stimulates protein kinase C (PKC)-dependent pathways, by forskolin (FSK), which stimulates protein kinase A (PKA)-dependent pathways, and by the use of various protein kinase inhibitors. Treatment with PMA stimulated AP-1 gene expression and DNA binding activity similar to the effects noted with BBS; FSK stimulated jun-B expression but produced only minimal increases of c- jun mRNA and AP-1 binding activity. Pretreatment of SIIA cells with either H-7 or H-8 (primarily PKC inhibitors) inhibited the induction of c- jun and jun-B mRNAs in response to BBS, whereas H-89 (PKA inhibitor) exhibited only minimal effects. Pretreatment with tyrphostin-25, a protein tyrosine kinase (PTK) inhibitor, attenuated the BBS-mediated induction of c- jun and jun-B, but the effect was not as pronounced as with H-7. Collectively, our results demonstrate that BBS acts through its receptor to produce a rapid induction of both c- jun and jun-B mRNA and AP-1 DNA binding activity in the SIIA human gastric cancer. Moreover, this induction of AP-1, in response to BBS, is mediated through both PKC- and PTK-dependent signal transduction pathways with only minimal involvement of PKA.

scholarly journals M-phase-specific phosphorylation of the POU transcription factor GHF-1 by a cell cycle-regulated protein kinase inhibits DNA binding.

1995 ◽  
Vol 15 (12) ◽  
pp. 6694-6701 ◽  
Author(s):  
C Caelles ◽  
H Hennemann ◽  
M Karin
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Protein Kinase ◽  
Dna Binding ◽  
Binding Activity ◽  
Dependent Manner ◽  
Mitotic Kinase ◽  
Dna Binding Activity ◽  
M Phase ◽  
A Cell

GHF-1 is a member of the POU family of homeodomain proteins. It is a cell-type-specific transcription factor responsible for determination and expansion of growth hormone (GH)- and prolactin-expressing cells in the anterior pituitary. It was previously suggested that cyclic AMP (cAMP)-responsive protein kinase A (PKA) phosphorylates GHF-1 at a site within the N-terminal arm of its homeodomain, thereby inhibiting its binding to the GH promoter. These results, however, are inconsistent with the physiological stimulation of GH production by the cAMP pathway. As reported here, cAMP agonists and PKA do not inhibit GHF-1 activity in living cells and although they stimulate the phosphorylation of GHF-1, the inhibitory phosphoacceptor site within the homeodomain is not affected. Instead, this site, Thr-220, is subject to M-phase-specific phosphorylation. As a result, GHF-1 DNA binding activity is transiently inhibited during the M phase. This activity is regained once cells enter G1, a phase during which GHF-1 phosphorylation is minimal. Thr-220 of GHF-1 is the homolog of the mitotic phosphoacceptor site responsible for the M-phase-specific inhibition of Oct-1 DNA binding Ser-382. As this site is conserved in all POU proteins, it appears that all members of this group are similarly regulated. A specific kinase activity distinct in its substrate specificity and susceptibility to inhibitors from the Cdc2 mitotic kinase or PKA was identified in extracts of mitotic cells. This novel activity could be involved in regulating the DNA binding activity of all POU proteins in a cell cycle-dependent manner.

A cyclin A-protein kinase complex possesses sequence-specific DNA binding activity: p33cdk2 is a component of the E2F-cyclin A complex

Cell ◽  
1992 ◽  
Vol 68 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Stephen H. Devoto ◽  
Maria Mudryj ◽  
Jonathon Pines ◽  
Tony Hunter ◽  
Joseph R. Nevins
Keyword(s):  
Protein Kinase ◽  
Dna Binding ◽  
Cyclin A ◽  
Binding Activity ◽  
Dna Binding Activity

Activation of protein kinase C decreases phosphorylation of c-Jun at sites that negatively regulate its DNA-binding activity

Cell ◽  
1991 ◽  
Vol 64 (3) ◽  
pp. 573-584 ◽  
Author(s):  
William J. Boyle ◽  
Tod Smeal ◽  
Libert H.K. Defize ◽  
Peter Angel ◽  
James R. Woodgett ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Dna Binding ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Kinase C

scholarly journals Cross-coupling of signal transduction pathways: the dioxin receptor mediates induction of cytochrome P-450IA1 expression via a protein kinase C-dependent mechanism.

1993 ◽  
Vol 13 (1) ◽  
pp. 677-689 ◽  
Author(s):  
A Berghard ◽  
K Gradin ◽  
I Pongratz ◽  
M Whitelaw ◽  
L Poellinger
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Dna Binding ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Kinase C ◽  
The Individual ◽  
Dioxin Receptor

Signal transduction by dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) is mediated by the intracellular dioxin receptor which, in its dioxin-activated state, regulates transcription of target genes encoding drug-metabolizing enzymes, such as cytochrome P-450IA1 and glutathione S-transferase Ya. Exposure of the dioxin receptor to dioxin leads to an apparent translocation of the receptor to the nucleus in vivo and to a rapid conversion of the receptor from a latent, non-DNA-binding form to a species that binds to dioxin-responsive positive control elements in vitro. This DNA-binding form of receptor appears to be a heterodimeric complex with the helix-loop-helix factor Arnt. In this study, we show that activation of the cytochrome P-450IA1 gene and minimal dioxin-responsive reporter constructs by the dioxin receptor was inhibited following prolonged treatment of human keratinocytes with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate. Inhibition of the receptor-mediated activation response was also achieved by treatment of the cells with a number of protein kinase inhibitors, one of which, calphostin C, shows selectivity for protein kinase C. Taken together, these data suggest that protein kinase C-dependent phosphorylation may play an essential role in the dioxin signaling pathway. This hypothesis is supported by the observation that pretreatment of the cells with 12-O-tetradecanoylphorbol-13-acetate inhibited the DNA-binding activity of the dioxin receptor in vivo. In vivo, the dioxin receptor was found to be a phosphoprotein. In vitro, dephosphorylation of the ligand-activated, heteromeric dioxin receptor form or dephosphorylation of the individual ligand-binding and Arnt receptor subunits inhibited the xenobiotic response element-binding activity. Moreover, dephosphorylation experiments with the individual receptor subunits prior to assembly of the xenobiotic response element-binding receptor form indicated that phosphorylation seemed to be important for the DNA-binding activity per se of the receptor, whereas Arnt appeared to require phosphorylation to interact with the receptor. Finally, a protein kinase C inhibitor-sensitive cytosolic catalytic activity that could restore the DNA-binding activity of the dephosphorylated dioxin receptor form was identified.

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