화학공학소재연구정보센터
Biochemical and Biophysical Research Communications, Vol.391, No.1, 78-84, 2010
Regulation of phosphorylation at the postsynaptic density during different activity states of Ca2+/calmodulin-dependent protein kinase II
Ca2+/calmodulin-dependent protein kinase II (CaMKII), the most abundant kinase at the postsynaptic density (PSD), is expected to be involved in activity-induced regulation of synaptic properties CaMKII is activated when it binds calmodulin in the presence of Ca2+ and, once autophosphorylated on T-286/7, remains active in the absence of Ca2+ (autonomous form). In the present study we used a quantitative mass spectrometric strategy (iTRAQ) to identify sites on PSD components phosphorylated upon CaMKII activation Phosphorylation in isolated PSDs was monitored under conditions where CaMKII is (1) mostly inactive (basal state), (2) active in the presence of Ca2+, and (3) active in the absence of Ca2+. The quantification strategy was validated through confirmation of previously described autophosphorylation characteristics of CaMKII. The effectiveness of phosphorylation of major PSD components by the activated CaMKII in the presence and absence of Ca2+ varied. Most notably, autonomous activity in the absence of Ca2+ was more effective in the phosphorylation of three residues on SynGAP Several PSD scaffold proteins were phosphorylated upon activation of CaMKII. The strategy adopted allowed the identification, for the first time, of CaMKII-regulated sites on SAPAPs and Shanks, including three conserved serine residues near the C-termini of SAPAP1, SAPAP2, and SAPAP3. Involvement of CaMKII in the phosphorylation of PSD scaffold proteins suggests a role in activity-induced structural re-organization of the PSD. Published by Elsevier Inc.