A plasma membrane Ca2+ ATPase isoform at the postsynaptic density.
Most excitatory input in the hippocampus impinges on dendritic spines. Entry of Ca(2+) into spines through NMDA receptors can trigger a sequence of biochemical reactions leading to sustained changes in synaptic efficacy. To provide specificity, dendritic spines restrict the diffusion of Ca(2+) signaling and downstream molecules. The postsynaptic density (PSD) (the most prominent subdomain within the spine) is the site of Ca(2+) entry through NMDA receptors. We here demonstrate that Ca(2+) can also be removed via pumps embedded in the PSD. Using light- and electron-microscopic immunohistochemistry, we find that PMCA2w, a member of the plasma membrane Ca(2+)-ATPase (PMCA) family, concentrates at the PSD of most hippocampal spines. We propose that PMCA2w may be recruited into supramolecular complexes at the postsynaptic density, thus helping to regulate Ca(2+) nanodomains at subsynaptic sites. Taken together, these results suggest a novel function for PMCAs as modulators of Ca(2+) signaling at the synapse.
Burette
A C
AC
Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, 314 Taylor Hall, CB# 7090, Chapel Hill, NC 27599, USA. alain_burette@med.unc.edu
Strehler
E E
EE
Weinberg
R J
RJ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D049229:Dendritic Spines / Q000201:enzymology; D006624:Hippocampus / Q000201:enzymology / Q000648:ultrastructure; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism; D008297:Male; D053499:Plasma Membrane Calcium-Transporting ATPases / Q000378:metabolism*; D017966:Pyramidal Cells / Q000201:enzymology / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000378:metabolism*
D007527:Isoenzymes; D053499:Plasma Membrane Calcium-Transporting ATPases; D002118:Calcium