Activation of CA2+/calmodulin-dependent protein kinase IV in cultured rat hippocampal neurons

✍ Scribed by Jiro Kasahara; Kohji Fukunaga; Eishichi Miyamoto

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 147 KB
• Volume: 59
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/(sici)1097-4547(20000301)59:5<594::aid-jnr2>3.0.co;2-q

✦ Synopsis

Ca 2ϩ /calmodulin-dependent protein kinase IV (CaM kinase IV) is a multifunctional enzyme that is abundantly present in the nuclei of neurons. We report the properties of phosphorylation and activation of CaM kinase IV in comparison to CaM kinase II in cultured rat hippocampal neurons. Phosphorylation and activity of CaM kinase IV as well as CaM kinase II were increased by treatment of neurons either with glutamate or high K ϩ . Glutamateinduced phosphorylation and activity of CaM kinase IV were blocked by N-methyl-D-asparate (NMDA) antagonists, and NMDA application instead of glutamate did increase CaM kinase IV phosphorylation. CaM kinase IV phosphorylation was also increased by ␣-amino-3hydroxy-5-methyl-4-isoxazolepropionate (AMPA), and was blocked by an inhibitor of NMDA receptor. The AMPA-induced phosphorylation was blocked by tetrodotoxin, a Na ϩ channel blocker, that was expected to block endogenous glutamate transmission indirectly. On the other hand, high K ϩ -induced phosphorylation and activation were not blocked by inhibitors of glutamate receptors, and effectively blocked by nifedipine, an L-type Ca 2ϩ channel blocker. These properties were similar between CaM kinase IV and CaM kinase II.