TY - JOUR
T1 - Protein kinase CK2 in postsynaptic densities
T2 - Phosphorylation of PSD-95/SAP90 and NMDA receptor regulation
AU - Soto, Dagoberto
AU - Pancetti, Floria
AU - Marengo, Juan José
AU - Sandoval, Mauricio
AU - Sandoval, Rodrigo
AU - Orrego, Fernando
AU - Wyneken, Ursula
N1 - Funding Information:
We thank Professor Dr. Jorge Allende for helpful comments, and Fermelo for providing us with Amersham equipment. This work was supported by Fondecyt Project 1020257 and by Universidad de los Andes Projects.
PY - 2004/9/17
Y1 - 2004/9/17
N2 - Protein kinase CK2 (CK2) is highly expressed in rat forebrain where its function is not well understood. Subcellular distribution studies showed that the catalytic subunit of CK2 (CK2α) was enriched in postsynaptic densities (PSDs) by 68%. We studied the putative role of CK2 activity on N-methyl-d-aspartate receptor (NMDAR) function using isolated, patch-clamped PSDs in the presence of 2 mM extracellular Mg 2+. The usual activation by phosphorylation of the NMDARs in the presence of ATP was inhibited by the selective CK2 inhibitor 5,6-dichloro-1-β-ribofuranosyl benzimidazole (DRB). This inhibition was voltage-dependent, i.e., 100% at positive membrane potentials, while at negative potentials, inhibition was incomplete. Endogenous CK2 substrates were characterized by their ability to use GTP as a phosphoryl donor and susceptibility to inhibition by DRB. Immunoprecipitation assays and 2D gels indicated that PSD-95/SAP90, the NMDAR scaffolding protein, was a CK2 substrate, while the NR2A/B and NR1 NMDAR subunits were not. These results suggest that postsynaptic NMDAR regulation by CK2 is mediated by indirect mechanisms possibly involving PSD-95/SAP90.
AB - Protein kinase CK2 (CK2) is highly expressed in rat forebrain where its function is not well understood. Subcellular distribution studies showed that the catalytic subunit of CK2 (CK2α) was enriched in postsynaptic densities (PSDs) by 68%. We studied the putative role of CK2 activity on N-methyl-d-aspartate receptor (NMDAR) function using isolated, patch-clamped PSDs in the presence of 2 mM extracellular Mg 2+. The usual activation by phosphorylation of the NMDARs in the presence of ATP was inhibited by the selective CK2 inhibitor 5,6-dichloro-1-β-ribofuranosyl benzimidazole (DRB). This inhibition was voltage-dependent, i.e., 100% at positive membrane potentials, while at negative potentials, inhibition was incomplete. Endogenous CK2 substrates were characterized by their ability to use GTP as a phosphoryl donor and susceptibility to inhibition by DRB. Immunoprecipitation assays and 2D gels indicated that PSD-95/SAP90, the NMDAR scaffolding protein, was a CK2 substrate, while the NR2A/B and NR1 NMDAR subunits were not. These results suggest that postsynaptic NMDAR regulation by CK2 is mediated by indirect mechanisms possibly involving PSD-95/SAP90.
KW - Excitatory neurotransmission
KW - NMDA receptor
KW - PSD-95/SAP90
KW - Postsynaptic density
KW - Protein kinase CK2
KW - Rat forebrain
UR - http://www.scopus.com/inward/record.url?scp=6044250387&partnerID=8YFLogxK
U2 - 10.1016/j.bbrc.2004.07.158
DO - 10.1016/j.bbrc.2004.07.158
M3 - Article
C2 - 15325264
AN - SCOPUS:6044250387
VL - 322
SP - 542
EP - 550
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 2
ER -