scholarly journals Mitogen-Activated Protein Kinase and Cell Cycle Progression During Mouse Egg Activation Induced by Various Stimuli

1999 ◽  
Vol 54 (3-4) ◽  
pp. 285-294 ◽  
Author(s):  
Q. Y. Sun ◽  
Y. Lax ◽  
S. Rubinstein ◽  
D. Y. Chen ◽  
H. Breitbart

Abstract A very sensitive method was established for detecting the activity of mitogen-activated protein (MAP) kinase in mouse eggs, and used to follow temporal changes of this kinase during fertilization and sponatenous or chemically-induced parthenogenic activation. MAP kinase activity increased between 1 and 2.5 h post-insemination, at which time the second polar body was emitted and sperm chromatin was dispersed; its activity decreased sharply at 8 h, when pronuclei were formed. Both calcium ionophore A23187 and ethanol simulta­ neously induced pronuclear formation and MAP kinase inactivation in aged eggs 8 h after incubation but less effectively in fresh eggs. The protein kinase inhibitor staurosporine in­duced pronuclear formation and MAP kinase inactivation more quickly than other treat­ ments, with MAP kinase inactivation occurring slightly proceeding pronuclear formation. Okadaic acid, a specific inhibitor of protein phosphatase 1 and 2A , induced increase in MAP kinase activity, and overcame pronuclear formation induced by various stimuli. MAP kinase inactivation preceded pronuclear formation in eggs spontaneously activated by aging in vitro, perhaps due to cytoplasmic degeneration and thus delayed response of nuclear envelope precursors to MAP kinase inactivation. These data suggest that MAP kinase is a key protein kinase regulating the events of mouse egg activation. Increased MAP kinase activity is temporally correlated with the second polar body emission and sperm chromatin decondensation. Although different stimuli (including sperm) may initially act through different mechanisms, they finally inactivate MAP kinase, probably by allowing the action of protein phosphatase, and thus induces the transition to interphase.

Zygote ◽  
1995 ◽  
Vol 3 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Maki Inoue ◽  
Kunihiko Naito ◽  
Fugaku Aoki ◽  
Yutaka Toyoda ◽  
Eimei Sato

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.


2007 ◽  
Vol 19 (1) ◽  
pp. 282
Author(s):  
L. Nanassy ◽  
K. Lee ◽  
A. Javor ◽  
Z. Machaty

Cell cycle progression during mitosis and meiosis is known to be regulated by the M-phase promoting factor (MPF). However, recent findings revealed that mitogen-activated protein kinase (MAPK) also plays an important regulatory role during transition through the cell cycle. At fertilization the activity of MAPK drops shortly after MPF inactivation; the objective of this study was to investigate the dynamics of MAPK activity in pig oocytes after different activation methods. In vitro-matured oocytes were allocated to 3 groups. In group 1 (EP), the oocytes were activated by 2 DC pulses of 1.2 kV cm-1, 60 �s each. In the second group (EP + BU), the oocytes were electroporated and incubated for 4 h in 100 �M butyrolactone I (BU, an inhibitor of cdc2 kinase). In group 3 (EP + CHX), the oocytes were electroporated and treated for 5 h with 10 �g mL-1 cycloheximide (CHX, a protein synthesis inhibitor). After electroporation all oocytes were incubated in 7.5 �g mL-1 cytochalasin B for 4 h. Some oocytes were used to determine MAPK activity at 0, 1, 2, 3, 4, 5, and 6 h after electroporation using a MAPK assay kit. The assay measures MAPK activity by determining the phosphorylation of myelin basic protein by MAPK using the transfer of the γ-phosphate of [γ-32P] ATP. Pronuclear formation was evaluated at 6 h after electroporation; blastocyst formation and total cell numbers per embryo were determined after a 7-day culture in PZM-3 medium. Pronuclear formation was compared by the chi-square test, blastocyst formation was assessed using ANOVA, and the kinase activity was evaluated using the Student t-test. Pronuclear formation was highest in the combined methods [69.39% (EP) vs. 86.32% (EP + BU) and 87.56 % (EP + CHX); P < 0.05]. Similarly, the combined methods supported better development to the blastocyst stage [25.06 � 7.96% (EP), 58.32 � 7.62% (EP + BU), and 63.91 � 6.35% (EP + CHX); P < 0.05], whereas the average cell numbers of the blastocysts did not differ (47.11 � 3.12, 46.56 � 2.33, and 44.04 � 1.86, respectively). The initial MAPK activity was 0.123 � 0.017 pmol/min/oocyte which, after 1 h, dropped in all cases to values of 0.069 � 0.009 (EP), 0.072 � 0.007 (EP + BU), and 0.077 � 0.012 (EP + CHX) pmol/min/oocyte (P < 0.05). The MAPK activity in the EP group reached its lowest level at 3 h (0.057 � 0.007 pmol/min/oocyte); however, at 4 h it started to recover and by 6 h the activity (0.079 � 0.022 pmol/min/oocyte) did not differ from that of the non-activated oocytes. In the other groups, MAPK activity stayed low, and by the end of the experimental period it was significantly lower than that in the nontreated metaphase II oocytes (P < 0.05). The results indicate that electroporation followed by protein kinase inhibition or protein synthesis inhibition leads to the efficient inactivation of MAPK activity, and confirm our earlier findings that these combined treatments support superior embryo development after oocyte activation.


2016 ◽  
Vol 310 (11) ◽  
pp. C921-C930 ◽  
Author(s):  
Danielle M. Trappanese ◽  
Sarah Sivilich ◽  
Hillevi K. Ets ◽  
Farah Kako ◽  
Michael V. Autieri ◽  
...  

Vascular smooth muscle contraction is primarily regulated by phosphorylation of myosin light chain. There are also modulatory pathways that control the final level of force development. We tested the hypothesis that protein kinase C (PKC) and mitogen-activated protein (MAP) kinase modulate vascular smooth muscle activity via effects on MAP kinase phosphatase-1 (MKP-1). Swine carotid arteries were mounted for isometric force recording and subjected to histamine stimulation in the presence and absence of inhibitors of PKC [bisindolylmaleimide-1 (Bis)], MAP kinase kinase (MEK) (U0126), and MKP-1 (sanguinarine) and flash frozen for measurement of MAP kinase, PKC-potentiated myosin phosphatase inhibitor 17 (CPI-17), and caldesmon phosphorylation levels. CPI-17 was phosphorylated in response to histamine and was inhibited in the presence of Bis. Caldesmon phosphorylation levels increased in response to histamine stimulation and were decreased in response to MEK inhibition but were not affected by the addition of Bis. Inhibition of PKC significantly increased p42 MAP kinase, but not p44 MAP kinase. Inhibition of MEK with U0126 inhibited both p42 and p44 MAP kinase activity. Inhibition of MKP-1 with sanguinarine blocked the Bis-dependent increase of MAP kinase activity. Sanguinarine alone increased MAP kinase activity due to its effects on MKP-1. Sanguinarine increased MKP-1 phosphorylation, which was inhibited by inhibition of MAP kinase. This suggests that MAP kinase has a negative feedback role in inhibiting MKP-1 activity. Therefore, PKC catalyzes MKP-1 phosphorylation, which is reversed by MAP kinase. Thus the fine tuning of vascular contraction is due to the concerted effort of PKC, MAP kinase, and MKP-1.


1991 ◽  
Vol 11 (2) ◽  
pp. 1002-1008
Author(s):  
G L'Allemain ◽  
T W Sturgill ◽  
M J Weber

Mitogen-activated protein (MAP) kinase is a serine/threonine-specific protein kinase which is activated in response to various mitogenic agonists (e.g., epidermal growth factor, insulin, and the tumor promoter tetradecanoyl phorbol acetate [TPA]) and requires both threonine and tyrosine phosphorylation for activity. This enzyme has recently been shown to be identical or closely related to pp42, a protein which becomes tyrosine phosphorylated in response to mitogenic stimulation. Neither the kinases which regulate MAP kinase/pp42 nor the in vivo substrates for this enzyme are known. Because MAP MAP kinase is activated and phosphorylated in response both to agents which stimulate tyrosine kinase receptors and to agents which stimulate protein kinase C, a serine/threonine kinase, we have examined the regulation and phosphorylation of this enzyme in 3T3-TNR9 cells, a variant cell line partially defective in protein kinase C-mediated signalling. In this communication, we show that in the 3T3-TNR9 variant cell line, TPA does not cause the characteristically rapid phosphorylation of pp42 or the activation and phosphorylation of MAP kinase. This defective response is not due to the absence of the MAP kinase/pp42 protein itself because both tyrosine phosphorylation of MAP kinase/pp42 and its enzymatic activation could be induced by platelet-derived growth factor in the 3T3-TNR9 cells. Thus, the defect in these variant cells apparently resides in some aspect of the regulation of MAP kinase phosphorylation. Since the 3T3-TNR9 cells are also defective with respect to the TPA-induced increase in ribosomal protein S6 kinase, these in vivo results reinforce the earlier in vitro finding that MAP kinase can regulate S6 kinase activity. These findings suggest a key role for MAP kinase in a kinase cascade cascade involved in the control of cell proliferation.


2005 ◽  
Vol 387 (3) ◽  
pp. 627-637 ◽  
Author(s):  
Yoshikazu TSUMURA ◽  
Jiro TOSHIMA ◽  
Onno C. LEEKSMA ◽  
Kazumasa OHASHI ◽  
Kensaku MIZUNO

TESK1 (testicular protein kinase 1) is a serine/threonine kinase that phosphorylates cofilin and plays a critical role in integrin-mediated actin cytoskeletal reorganization and cell spreading. We previously showed that TESK1 interacts with Sprouty-4 (referred to as Spry4), an inhibitor of growth factor-induced Ras/MAP (mitogen-activated protein) kinase signalling, but the functional role of this interaction has remained unknown. In the present study, we show that Spry4 inhibits the kinase activity of TESK1 by binding to it through the C-terminal cysteine-rich region. Expression of Spry4 in cultured cells suppressed integrin-mediated cell spreading, and TESK1 reversed the inhibitory effect of Spry4 on cell spreading. Furthermore, Spry4 suppressed integrin- and TESK1-mediated cofilin phosphorylation during the spreading of cells on laminin. These findings suggest that Spry4 suppresses cell spreading by inhibiting the kinase activity of TESK1. Although tyrosine phosphorylation is required for the inhibitory activity of Spry4 on a Ras/MAP kinase pathway, mutation of the corresponding tyrosine residue (Tyr-75 in human Spry4) to an alanine had no apparent effect on its inhibitory actions on TESK1 activity and cell spreading, which suggests a novel cellular function of Spry to regulate the actin cytoskeleton, independent of its inhibitory activity on the Ras/MAP kinase signalling.


Zygote ◽  
2001 ◽  
Vol 9 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Hideki Tatemoto ◽  
Norio Muto

The decrease in maturation-promoting factor (MPF) activity precedes that in mitogen-activated protein kinase (MAPK) activity after egg activation, but the cellular functions of this delayed inactivation of MAPK are still unclear. The present study was conducted to examine the essential role of MAPK activity for supporting the transition from metaphase to interphase in porcine oocytes matured in vitro. The increases in the phosphorylated forms of MAPK and the activities of MAPK and histone H1 kinase (H1K) were shown in oocytes arrested at the metaphase II (MII) stage. After additional incubation of MII-arrested oocytes in medium with added U0126, a specific inhibitor of MAPK kinase, 24% of oocytes completed the second meiotic division and underwent entry into interphase with pronucleus (PN) formation, but not second polar body (PB-2) emission. The intensities of the phosphorylated forms of MAPK and the activities of MAPK and H1K in matured oocytes treated with U0126 were significantly decreased by the treatment with U0126. Electrostimulation to induce artificial activation caused both H1K and MAPK inactivation; the inactivation of H1K preceded the inactivation of MAPK and sustained high levels of MAPK activity were detected during the period of PB-2 emission. However, the time sequence required for MAPK inactivation was significantly reduced by the addition of U0126 to the culture medium following electrostimulation, resulting in the dramatic inactivation of MAPK distinct from that of H1K. In these oocytes, PB-2 emission was markedly inhibited but little difference was found in the time course of PN formation compared with oocytes not treated with U0126. These findings suggest that the decrease in MAPK activity is partly involved in driving matured oocytes out of metaphase to induce PN development, and that the delayed MAPK inactivation after the onset of MPF inactivation in activated oocytes has a crucial role for PB-2 emission to accomplish the transition from meiosis to mitosis.


Reproduction ◽  
2004 ◽  
Vol 128 (4) ◽  
pp. 409-415 ◽  
Author(s):  
Junya Ito ◽  
Natsuko Kawano ◽  
Masumi Hirabayashi ◽  
Masayuki Shimada

The objective of this study was to investigate the role of calmodulin-dependent protein kinase II (CaMKII) during fertilization in the pig. Since it has been reported that CaMKII is involved in the capacitation and acrosome reaction of spermatozoa, we tested whether supplementation with the CaMKII inhibitor, KN-93, in the fertilization medium affected sperm penetration. The results showed that the addition of KN-93 in the fertilization medium significantly reduced the rate of sperm penetration into oocytes. However, pre-treatment with KN-93 beforein vitrofertilization (IVF) did not significantly affect sperm penetration, but it did affect pronuclear formation in a dose-dependent manner. In the oocytes pre-treated with KN-93 before IVF and then co-cultured with spermatozoa without the drug, the decrease in p34cdc2kinase and the cyclin B1 level were significantly suppressed as compared with those in penetrated oocytes without treatment with KN-93. However, the decrease in MAP kinase activity was not affected by KN-93. Additional treatment with KN-93 after Ca2+ionophore treatment also inhibited the reduction in p34cdc2kinase activity and the cyclin B1 level, but not MAP kinase activity. Treatment with KN-92, an inactive KN-93 analogue, did not significantly affect sperm penetration and pronuclear formation. In conclusion, the activation of CaMKII by artificial stimuli or sperm stimulated the disruption of cyclin B1 and the inactivation of p34cdc2kinase, but did not affect MAP kinase inactivation during oocyte activation in pigs.


2002 ◽  
Vol 80 (5) ◽  
pp. 375-382 ◽  
Author(s):  
Louis M Luttrell

Over the past decade, it has become apparent that many G-protein-coupled receptors (GPCRs) generate signals that control cellular differentiation and growth, including stimulation of Ras family GTPases and activation of mitogen-activated protein (MAP) kinase pathways. The mechanisms that GPCRs use to control the activity of MAP kinases vary between receptor and cell type but fall broadly into one of three categories: signals initiated by classical G protein effectors, e.g., protein kinase (PK)A and PKC, signals initiated by cross-talk between GPCRs and classical receptor tyrosine kinases, e.g., "transactivation" of epidermal growth factor (EGF) receptors, and signals initiated by direct interaction between β-arrestins and components of the MAP kinase cascade, e.g., β-arrestin "scaffolds". While each of these pathways results in increased cellular MAP kinase activity, emerging data suggest that they are not functionally redundant. MAP kinase activation occurring via PKC-dependent pathways and EGF receptor transactivation leads to nuclear translocation of the kinase and stimulates cell proliferation, while MAP kinase activation via β-arrestin scaffolds primarily increases cytosolic kinase activity. By controlling the spatial and temporal distribution of MAP kinase activity within the cell, the consequences of GPCR-stimulated MAP kinase activation may be determined by the mechanism by which they are activated.Key words: G-protein-coupled receptor, receptor tyrosine kinase, β-arrestin, mitogen-activated protein kinase, extracellular signal-regulated kinase.


1991 ◽  
Vol 11 (2) ◽  
pp. 1002-1008 ◽  
Author(s):  
G L'Allemain ◽  
T W Sturgill ◽  
M J Weber

Mitogen-activated protein (MAP) kinase is a serine/threonine-specific protein kinase which is activated in response to various mitogenic agonists (e.g., epidermal growth factor, insulin, and the tumor promoter tetradecanoyl phorbol acetate [TPA]) and requires both threonine and tyrosine phosphorylation for activity. This enzyme has recently been shown to be identical or closely related to pp42, a protein which becomes tyrosine phosphorylated in response to mitogenic stimulation. Neither the kinases which regulate MAP kinase/pp42 nor the in vivo substrates for this enzyme are known. Because MAP MAP kinase is activated and phosphorylated in response both to agents which stimulate tyrosine kinase receptors and to agents which stimulate protein kinase C, a serine/threonine kinase, we have examined the regulation and phosphorylation of this enzyme in 3T3-TNR9 cells, a variant cell line partially defective in protein kinase C-mediated signalling. In this communication, we show that in the 3T3-TNR9 variant cell line, TPA does not cause the characteristically rapid phosphorylation of pp42 or the activation and phosphorylation of MAP kinase. This defective response is not due to the absence of the MAP kinase/pp42 protein itself because both tyrosine phosphorylation of MAP kinase/pp42 and its enzymatic activation could be induced by platelet-derived growth factor in the 3T3-TNR9 cells. Thus, the defect in these variant cells apparently resides in some aspect of the regulation of MAP kinase phosphorylation. Since the 3T3-TNR9 cells are also defective with respect to the TPA-induced increase in ribosomal protein S6 kinase, these in vivo results reinforce the earlier in vitro finding that MAP kinase can regulate S6 kinase activity. These findings suggest a key role for MAP kinase in a kinase cascade cascade involved in the control of cell proliferation.


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