Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Roles of Ca2+ and protein kinase C (PKC) in the regulation of acid/base transport in isolated rabbit proximal tubules were investigated by measuring cytosolic Ca2+ concentrations ([Ca2+]i) and cell pH (pHi) with fluorescent probes. Ionomycin (0.2 microM) increased [Ca2+]i by approximately 200 nM but did not affect the basolateral Na(+)-HCO3- cotransporter. However, the apical Na+/H+ exchanger was inhibited by 50% by ionomycin, and this inhibition was abolished either by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, an intracellular Ca2+ chelator, or by KN-62, an inhibitor of calcium-calmodulin-dependent protein kinase II (CaM kinase II). On the other hand, phorbol 12-myristate 13-acetate (PMA, 0.5 microM) did not affect the apical Na+/H+ exchanger but did stimulate the basolateral Na(+)-HCO3- cotransporter by 60-80%, and this stimulation was prevented by calphostin C, an inhibitor of PKC. Consistent with the cotransporter stimulation, PMA decreased steady-state pHi in the presence of CO2/ HCO3-. These results indicate that 1) the acute increase in [Ca2+]i within physiological ranges inhibits the apical Na+/H+ exchanger, probably through mediation of CaM kinase II; and 2) the short-term PKC activation stimulates the basolateral Na(+)-HCO3- cotransporter.
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PMID:Roles of Ca2+ and PKC in regulation of acid/base transport in isolated proximal tubules. 894 2

Previous studies have shown that hypocapnia results in fragmentation of nuclear DNA in the cerebral cortex of newborn piglets. We tested the hypothesis that hypocapnia results in decreased ATP and phosphocreatine (PCr) levels and increased nuclear high-affinity Ca++-ATPase activity, intranuclear Ca++ flux, and CaM kinase IV activity in neuronal nuclei of piglets. Three groups of piglets were ventilated as either hypocapnic (a PaCO2 of 20 mm Hg), normocapnic (a PaCO2 of 40 mm Hg), or corrected hypocapnic (ventilated as hypocapnic but with CO2 added to maintain normocapnia) for 1 h. Tissue ATP levels were lower in the hypocapnic than in the normocapnic group. PCr levels were lower and 45Ca++-influx, Ca++-ATPase activity and CaM kinase IV activity were higher in hypocapnic than in normocapnic or corrected hypocapnic piglets. We conclude that hypocapnia alters nuclear membrane Ca++ flux mechanisms and may alter neuronal phosphorylation mechanisms in the cerebral cortex of piglets.
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PMID:The effect of moderate hypocapnic ventilation on nuclear Ca2+-ATPase activity, nuclear Ca2+ flux, and Ca2+/calmodulin kinase IV activity in the cerebral cortex of newborn piglets. 1509 43