Calpain-mediated degradation of PSD-95 in developing and adult rat brain.
PSD-95 is a major postsynaptic density protein that is degraded as a result of synaptic activity. We used four different methods to test the hypothesis that calpain is involved in PSD-95 turnover. Treatment of synaptic membranes with purified calpain resulted in a decrease in immunoreactivity of the native 95 kDa protein and the appearance of two smaller molecular weight species, migrating at 50 and 36 kDa, respectively. Calcium treatment of frozen-thawed brain sections produced an identical digestion pattern, an effect blocked by calpain inhibitors. N-methyl-D-aspartate treatment of organotypic hippocampal cultures produced truncation of PSD-95 and accumulation of the 36 kDa species. Finally, calpain-generated degradation products of PSD95 were prominent in neonatal hippocampus, and disappeared with postnatal development. Our data suggest that PSD-95 is a substrate for calpain, and that calpain-mediated truncation contributes to PSD-95 turnover.
Lu
X
X
HNB 124, Neuroscience Program, USC, Los Angeles, CA 90089-2520, USA.
Rong
Y
Y
Baudry
M
M
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002154:Calpain / Q000378:metabolism* / Q000494:pharmacology*; D002478:Cells, Cultured; D000076122:Disks Large Homolog 4 Protein; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D016202:N-Methylaspartate / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000187:drug effects* / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000187:drug effects* / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D018690:Excitatory Amino Acid Agonists; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C033652:postsynaptic density proteins; D016202:N-Methylaspartate; D002154:Calpain; D002118:Calcium