scholarly journals The role of calcium/calmodulin-dependent protein kinase II on the inactivation of MAP kinase and p34cdc2 kinase during fertilization and activation in pig oocytes

Reproduction ◽  
2004 ◽  
Vol 128 (4) ◽  
pp. 409-415 ◽  
Author(s):  
Junya Ito ◽  
Natsuko Kawano ◽  
Masumi Hirabayashi ◽  
Masayuki Shimada
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Kinase Activity ◽  
Cyclin B1 ◽  
Dependent Protein Kinase ◽  
Protein Kinase Ii ◽  
Sperm Penetration ◽  
Dependent Protein ◽  
Pronuclear Formation

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.

Ca2+/calmodulin-dependent protein kinase II activation and regulation of adrenal glomerulosa Ca2+ signaling

1995 ◽  
Vol 269 (6) ◽  
pp. F751-F760 ◽  
Author(s):  
R. J. Fern ◽  
M. S. Hahm ◽  
H. K. Lu ◽  
L. P. Liu ◽  
F. S. Gorelick ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Low Voltage ◽  
Extracellular Potassium ◽  
Dependent Protein Kinase ◽  
Calmodulin Antagonist ◽  
Cell Extracts ◽  
Protein Kinase Ii ◽  
Dependent Protein ◽  
A Cell

We recently reported that elevations in the intracellular Ca2+ concentration ([Ca2+]i) enhance low-voltage-activated, T-type, Ca2+ channel activity via Ca2+/calmodulin-dependent protein kinase II (CaMKII). Here, we document CaMKII activity in bovine adrenal glomerulosa (AG) cells and assess the importance of CaMKII in depolarization-induced Ca2+ signaling. AG cell extracts exhibited kinase activity toward a CaMKII-selective peptide substrate that was dependent on both Ca2+ [half-maximal concentration for Ca2+ activation (K0.5) = 1.5 microM] and calmodulin (K0.5 = 46 nM) and was sensitive to a calmodulin antagonist and a CaMKII peptide inhibitor. On cell treatment with elevated extracellular potassium (10-60 mM) or angiotensin II, Ca(2+)-independent CaMKII activity increased to 133-205% of basal activity. Ca(2+)-independent kinase activity in agonist-stimulated extracts was inhibited by the CaMKII inhibitor peptide, 1(-)[N,O-bis(1,5- isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62), a cell-permeable inhibitor of CaMKII, reduced the agonist-induced stimulation of Ca(2+)-independent CaMKII activity. KN-62 also diminished depolarization-induced increases in [Ca2+]i without affecting the membrane potential. These observations suggest that CaMKII is activated in situ by aldosterone secretagogues and augments Ca2+ signaling through voltage-gated Ca2+ channels.

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