Identification of the Ca2+/calmodulin-dependent protein kinase II regulatory phosphorylation site in the alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate-type glutamate receptor.
Ca2+/CaM-dependent protein kinase II (CaM-KII) can phosphorylate and potentiate responses of alpha-amino3-hydroxyl-5-methyl-4-isoxazole-propionate-type glutamate receptors in a number of systems, and recent studies implicate this mechanism in long term potentiation, a cellular model of learning and memory. In this study we have identified this CaM-KII regulatory site using deletion and site-specific mutants of glutamate receptor 1 (GluR1). Only mutations affecting Ser831 altered the 32P peptide maps of GluR1 from HEK-293 cells co-expressing an activated CaM-KII. Likewise, when CaM-KII was infused into cells expressing GluR1, the Ser831 to Ala mutant failed to show potentiation of the GluR1 current. The Ser831 site is specific to GluR1, and CaM-KII did not phosphorylate or potentiate current in cells expressing GluR2, emphasizing the importance of the GluR1 subunit in this regulatory mechanism. Because Ser831 has previously been identified as a protein kinase C phosphorylation site (Roche, K. W., O'Brien, R. J., Mammen, A. L., Bernhardt, J., and Huganir, R. L. (1996) Neuron 16, 1179-1188), this raises the possibility of synergistic interactions between CaM-KII and protein kinase C in regulating synaptic plasticity.
Barria
A
A
Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201, USA.
Derkach
V
V
Soderling
T
T
D019943:Amino Acid Substitution; D001665:Binding Sites; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002460:Cell Line; D004594:Electrophysiology; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D018091:Receptors, AMPA / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000378:metabolism
D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D018091:Receptors, AMPA; D011994:Recombinant Proteins; D012694:Serine