Mitogen-activated protein kinase activity and microtuble organisation are altered by protein synthesis inhibition in maturing porcine oocytes

Zygote ◽  
1996 ◽  
Vol 4 (3) ◽  
pp. 191-198 ◽  
Author(s):  
Maki Inoue ◽  
Kunihiko Naito ◽  
Taisuke Nakayama ◽  
Eimei Sato
Keyword(s):  
Protein Synthesis ◽  
Map Kinase ◽  
Kinase Activity ◽  
Germinal Vesicle ◽  
Protein Kinase Activity ◽  
Protein Synthesis Inhibition ◽  
Germinal Vesicle Breakdown ◽  
Kinase Activation ◽  
Synthesis Inhibition ◽  
Mitogen Activated Protein

SummaryPreviously we have shown that mitogen-activated protein (MAP) kinase activity abruptly increases at the first metaphase (M1) and remains significantly higher than that at the germinal vesicle (GV) stage until the second metaphase (M2) in porcine oocytes cultured in vitro. The present paper describes how the mechanism of the blockage of meiotic maturation by protein sythesis inhibition involves MAP kinase regulation. Cycloheximide arrested both germinal vesicle breakdown (GVBD) and the normal transition from M1 to M2. MAP kinase activation was also reduced in these maturation-inhibited oocytes. By using immunofluorescence microscopy with the monoclonal antibody raised against rat α-tubulin, we showed that cycloheximide caused morphological abnormality in a spindle at M1, but not at M2. All these results indicate that in porcine oocytes: (1) GV blockage by protein synthesis inhibition involves the suppression of both histone H1 kinase and MAP kinase activation, (2) during the transition from M1 to M2, maintenance of a normal metaphasic spindle and high MAP kinase activity require protein synthesis, and (3) once the M2 cytoskeletal structures have been completed, and/or after the ‘critical period’, cytostatic factor activity is independent of protein synthesis.

scholarly journals Endothelin stimulates mitogen-activated protein kinase activity in mesangial cells through ETA.

1994 ◽  
Vol 5 (4) ◽  
pp. 1074-1080
Author(s):  
Y Wang ◽  
J Pouysségur ◽  
M J Dunn
Keyword(s):  
Map Kinase ◽  
Map Kinases ◽  
Kinase Activity ◽  
Mesangial Cells ◽  
Chinese Hamster ◽  
Lung Fibroblasts ◽  
Protein Kinase Activity ◽  
Glomerular Mesangial Cells ◽  
Kinase Activation ◽  
Mitogen Activated Protein

Accumulating evidence suggests that endothelin (ET) contributes to the pathophysiology of such disorders as acute renal failure, cyclosporine-mediated renal and vascular toxicity, and perhaps even glomerular inflammation. The postreceptor signaling pathways that mediate the actions of ET in these pathophysiologic conditions may include activation of kinase cascades. Thus, the effects of ET isopeptides on p42 and p44 mitogen-activated protein (MAP) kinase activity in rat glomerular mesangial cells were examined. ET-1 activated both p42 and p44 MAP kinases with similar dose responses and different kinetics. The threshold for kinase activation was 10(-9) M ET-1. ET-1 stimulated p42 and p44 MAP kinases with similar rapid (5 min) but different sustained activation of p42 (3 to 6 h) and p44 (1 to 2 h). Endothelin-3 (ET-3) also activated both isoforms of MAP kinase but with a threshold at 10(-7) M. Compared with ET-1, ET-3 stimulated only a rapid increase of p42 MAP kinase activity. We further investigated which ET receptors are coupled to MAP kinase activation. BQ-123, an ETA blocker, completely blocked the responsiveness of the MAP kinase to either ET-1 or ET-3. In Chinese hamster lung fibroblasts transfected with ETA or ETB cDNA, both receptors showed a rapid stimulation of MAP kinase in response to ET-1. These results suggest that ET can activate MAP kinases through both ET receptors but act exclusively through ETA in glomerular mesangial cells.

cAMP inhibits mitogen-activated protein (MAP) kinase activation and resumption of meiosis, but exerts no effects after spontaneous germinal vesicle breakdown (GVBD) in mouse oocytes

1999 ◽  
Vol 11 (2) ◽  
pp. 81 ◽  
Author(s):  
Q. Y. Sun ◽  
Q. Lu ◽  
H. Breitbart ◽  
D. Y. Chen
Keyword(s):  
Map Kinase ◽  
Map Kinases ◽  
Specific Inhibitor ◽  
Germinal Vesicle ◽  
Germinal Vesicle Breakdown ◽  
Kinase Activation ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Kinase Phosphorylation ◽  
Pkc Activation

Various signaling molecules have been implicated in the oocyte G2/MII transition, including protein kinase C (PKC), cAMP and mitogen-activated protein (MAP) kinases. However, the cross-talk among these signaling pathways has not been elucidated. The present study demonstrates that both germinal vesicle break down (GVBD) and MAP kinase phosphorylation (activation) are inhibited when intraoocyte cAMP is increased by treating the GV-intact oocytes with dibutyryl cyclic AMP (dbcAMP), forskolin, or isobutylmethylxanthine (IBMX). Okadaic acid, a specific inhibitor of protein phosphatase-1 and -2A, completely overcame this effect. Calphostin C, a specific inhibitor of PKC, accelerated both GVBD and MAP kinase phosphorylation, and this effect was attenuated by increased intraoocyte cAMP, whereas PKC activation inhibited these events. Once GVBD occurred, the progression of oocyte maturation and MAP kinase phosphorylation were independent of cAMP. These results indicate that an increase in intraoocyte cAMP, in synergy with PKC activation, initiates a cascade of events resulting in inhibition of MAP kinase phosphorylation and GVBD in the mouse oocyte.

scholarly journals Role of receptor desensitization, phosphatase induction and intracellular cyclic AMP in the termination of mitogen-activated protein kinase activity in UTP-stimulated EAhy 926 endothelial cells

1996 ◽  
Vol 315 (2) ◽  
pp. 563-569 ◽  
Author(s):  
Anne GRAHAM ◽  
Angela McLEES ◽  
Kevin MALARKEY ◽  
Gwyn W. GOULD ◽  
Robin PLEVIN
Keyword(s):  
Endothelial Cells ◽  
Protein Synthesis ◽  
Map Kinase ◽  
Kinase Activity ◽  
Mitogen Activated Protein Kinase ◽  
Receptor Desensitization ◽  
Kinase Activation ◽  
Map Kinase Phosphatase ◽  
Mitogen Activated Protein ◽  
Map Kinase Kinase

We have investigated the mechanisms that bring about the termination of mitogen-activated protein kinase (MAP kinase) activation in response to UTP in EAhy 926 endothelial cells. UTP-stimulated MAP kinase activity was transient, returning to basal values by 60 min. At this time MAP kinase activation was desensitized; re-application of UTP did not further activate MAP kinase, full re-activation of MAP kinase being only apparent after a 1–2 h wash period. However, activation of MAP kinase by UTP could be sustained beyond 60 min by preincubation of the cells with the protein synthesis inhibitor cycloheximide. UTP also stimulated expression of MAP kinase phosphatase-1 and this was abolished after pretreatment with cycloheximide. Pretreatment of cells with forskolin abolished the initial activation of MAP kinase kinase or c-Raf-1 by UTP, but only affected MAP kinase activity during prolonged stimulation. The effect of forskolin on prolonged MAP kinase activation was also prevented by cycloheximide. These results suggest that the termination of MAP kinase activity in response to UTP involves a number of interacting mechanisms including receptor desensitization and the induction of a phosphatase. However, several pieces of evidence do not support a major role for MAP kinase phosphatase-1 in termination of the MAP kinase signal. Raising intracellular cyclic AMP may also be involved but only after an initial protein-synthesis step and by a mechanism that does not involve the inactivation of c-Raf-1 or MAP kinase kinase.

scholarly journals Activation of mitogen-activated protein kinase during meiotic maturation in porcine oocytes

Zygote ◽  
1995 ◽  
Vol 3 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Maki Inoue ◽  
Kunihiko Naito ◽  
Fugaku Aoki ◽  
Yutaka Toyoda ◽  
Eimei Sato
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Kinase Activity ◽  
Polar Body ◽  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
First Polar Body ◽  
Mitogen Activated Protein

SummaryTo investigate the involvement of mitogen-activated protein kinase(MAP kinase) in meiotic maturation of porcine oocytes, we assayed MAP kinase activity using basic protein(MBP) as a substrate. MAP kinase activity was low during the germinal vesicle stage, 0–20 h of culture. An abrupt increase was observed at metaphase I(30 h of culture), and activity remained significantly higher than that at 0 h until 50 h of culture, with a transient slight decrease at the time of first polar body extrusion (40 h). Detection of the kinase activity by an in-gel phosphorylation assay confirmed that the 42 and 44 kDa MAP kinases were significantly activated in 45 h cultured oocytes but not in 0 h oocytes, and just slightly in 20 h oocytes. In immunoblotting, however, the 42 and 44 kDa bands were detected in 0, 20 and 45 h cultured oocytes. Furthermore, the signal strength of the two bands did not change during the period of culture, but shifted up to 45 h, indicating that the activation of MAP kinase depended not on the synthesis but on the phosphorylation of this enzyme. These results suggest that the activation of MAP kinase is involved in the regulation of meiotic maturation of porcine oocytes, and especially in the regulation after germinal vesicle breakdown.

Histone H1 kinase activity, germinal vesicle breakdown and M phase entry in mouse oocytes

1994 ◽  
Vol 107 (1) ◽  
pp. 275-283 ◽  
Author(s):  
A.C. Gavin ◽  
J.C. Cavadore ◽  
S. Schorderet-Slatkine
Keyword(s):  
Protein Synthesis ◽  
Protein Kinase ◽  
Okadaic Acid ◽  
Kinase Activity ◽  
Germinal Vesicle ◽  
Histone H1 ◽  
Mitogen Activated Protein Kinase ◽  
Protein Kinase Activity ◽  
Germinal Vesicle Breakdown ◽  
Metaphase I

Meiotic reinitiation of the mouse oocyte is characterized by a slow entry into metaphase I, beginning with germinal vesicle breakdown and ending with spindle formation. It is accompanied by a cascade of protein kinases and phosphatases increasing protein phosphorylation. The activation of histone H1 kinase and that of the mitogen-activated protein kinase p42 have been compared during spontaneous or okadaic acid-induced meiotic reinitiation. In spontaneously maturing oocytes, histone H1 kinase activity increases before germinal vesicle breakdown (2-fold), in a protein synthesis-independent manner. It is associated with the disappearance of the upper migrating form of p34cdc2, which, in our system, seems to represent the tyrosine phosphorylated form. Following germinal vesicle breakdown, histone H1 kinase activity culminates (8-fold) in metaphase I and requires protein synthesis. Activation by phosphorylation of p42MAPK is observed as a permanent shift upward-migrating form and by its myelin basic protein kinase activity. It occurs after germinal vesicle breakdown and depends on protein synthesis. In contrast, no increase of histone H1 kinase is detectable in oocytes induced to reinitiate meiosis by a transient inhibition of okadaic acid-sensitive phosphatase(s), either before germinal vesicle breakdown or during the following 7 hours of culture. A slight increase is nevertheless evident after 17 hours, when oocytes are arrested with an abnormal metaphase I spindle. The upper migrating form of p34cdc2 is present for 8 hours. The activation of p42MAPK begins before germinal vesicle breakdown.(ABSTRACT TRUNCATED AT 250 WORDS)

Lysophosphatidylcholine activates mesangial cell PKC and MAP kinase by PLCγ-1 and tyrosine kinase-Ras pathways

1999 ◽  
Vol 277 (3) ◽  
pp. F328-F337 ◽  
Author(s):  
Babu V. Bassa ◽  
Daeyoung D. Roh ◽  
Nosratola D. Vaziri ◽  
Michael A. Kirschenbaum ◽  
Vaijinath S. Kamanna
Keyword(s):  
Tyrosine Kinase ◽  
Map Kinase ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Mesangial Cells ◽  
Kinase Activation ◽  
Kinase C ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Pkc Activation

Although lysophosphatidylcholine (LPC)-mediated cellular responses are attributed to the activation of protein kinase C (PKC), relatively little is known about the upstream signaling mechanisms that regulate the activation of PKC and downstream mitogen-activated protein (MAP) kinase. LPC activated p42 MAP kinase and PKC in mesangial cells. LPC-mediated MAP kinase activation was inhibited (but not completely) by PKC inhibition, suggesting additional signaling events. LPC stimulated protein tyrosine kinase (PTK) activity and induced Ras-GTP binding. LPC-induced MAP kinase activity was blocked by the PTK inhibitor genistein. Because LPC increased PTK activity, we examined the involvement of phospholipase Cγ-1 (PLCγ-1) as a key participant in LPC-induced PKC activation. LPC stimulated the phosphorylation of PLCγ-1. PTK inhibitors suppressed LPC-induced PKC activity, whereas the same had no effect on phorbol 12-myristate 13-acetate-mediated PKC activity. Other lysophospholipids [e.g., lysophosphatidylinositol and lysophosphatidic acid (LPA)] also induced MAP kinase activity, and only LPA-induced MAP kinase activation was sensitive to pertussis toxin. These results indicate that LPC-mediated PKC activation may be regulated by PTK-dependent activation of PLCγ-1, and both PKC and PTK-Ras pathways are involved in LPC-mediated downstream MAP kinase activation.

Microtubule and chromatin behavior follow MAP kinase activity but not MPF activity during meiosis in mouse oocytes

Development ◽  
1994 ◽  
Vol 120 (4) ◽  
pp. 1017-1025 ◽  
Author(s):  
M.H. Verlhac ◽  
J.Z. Kubiak ◽  
H.J. Clarke ◽  
B. Maro
Keyword(s):  
Cell Cycle ◽  
Myelin Basic Protein ◽  
Map Kinase ◽  
Kinase Activity ◽  
Basic Protein ◽  
Chromatin Condensation ◽  
Meiotic Maturation ◽  
Protein Kinase Activity ◽  
Microtubule Organization ◽  
Kinase Activation

Oocyte meiotic maturation is triggered by different stimuli (hormones, unknown signals through cell interactions) in different species. These stimuli indirectly lead to the activation of a major cell cycle regulating activity, the maturation promoting factor (MPF). Other factors, such as the product of the proto-oncogene c-mos or enzymes of the MAP kinase family, are also involved in the process of maturation. MAP kinase activation occurs during meiotic maturation in oocytes from different species with different kinetics. The relationships between MPF activation and MAP kinase activation have been well studied in species such as clam and Xenopus. In this paper, we study the precise timing of MAP kinase activation (as measured by phosphorylation of exogenous myelin basic protein and shifts in mobility of ERK 1 and ERK 2) versus MPF activation (as measured by phosphorylation of exogenous histone H1) during mouse oocyte maturation and, in parallel, morphological events such as changes in microtubule organization and chromatin condensation. We observed that MAP kinase activation was delayed after MPF activation and that this activity persisted throughout maturation whereas MPF activity dropped between the two meiotic metaphases. After parthenogenetic activation of ovulated eggs, MAP kinase inactivation was very slow compared to MPF inactivation. During the first mitotic cell cycle, a rise in myelin basic protein kinase activity at M-phase was observed but it was not related to MAP kinase activation. Furthermore, microtubules and chromatin remained in a metaphase-like state during the complete period of maturation (including the period between the two meiotic metaphases) and a few hours after activation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals RHO-associated protein kinase alpha potentiates insulin-induced MAP kinase activation in Xenopus oocytes

1999 ◽  
Vol 112 (13) ◽  
pp. 2177-2184 ◽  
Author(s):  
N. Ohan ◽  
Y. Agazie ◽  
C. Cummings ◽  
R. Booth ◽  
M. Bayaa ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Protein Kinase ◽  
Map Kinase ◽  
Insulin Receptor ◽  
Xenopus Oocytes ◽  
Germinal Vesicle ◽  
Insulin Receptor Substrate ◽  
Germinal Vesicle Breakdown ◽  
Kinase Activation ◽  
Insulin Signal Transduction

We recently identified Xenopus Rho-associated protein kinase alpha (xROKalpha) as a Xenopus insulin receptor substrate-1 binding protein and demonstrated that the non-catalytic carboxyl terminus of xROKalpha binds Xenopus insulin receptor substrate-1 and blocks insulin-induced MAP kinase activation and germinal vesicle breakdown in Xenopus oocytes. In the current study we further examined the role of xROKalpha in insulin signal transduction in Xenopus oocytes. We demonstrate that injection of mRNA encoding the xROKalpha kinase domain or full length xROKalpha enhanced insulin-induced MAP kinase activation and germinal vesicle breakdown. In contrast, injection of a kinase-dead mutant of xROKalpha or pre-incubation of oocytes with an xROKalpha inhibitor significantly reduced insulin-induced MAP kinase activation. To further dissect the mechanism by which xROKalpha may participate in insulin signalling, we explored a potential function of xROKalpha in regulating cellular Ras function, since insulin-induced MAP kinase activation and germinal vesicle breakdown is known to be a Ras-dependent process. We demonstrate that whereas injection of mRNA encoding c-H-Ras alone induced xMAP kinase activation and GVBD in a very low percentage (about 10%) of injected oocytes, co-injection of mRNA encoding xROKalpha and c-H-Ras induced xMAP kinase activation and germinal vesicle breakdown in a significantly higher percentage (50-60%) of injected oocytes. These results suggest a novel function for xROKalpha in insulin signal transduction upstream of cellular Ras function.

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