Protein ubiquitination in postsynaptic densities after transient cerebral ischemia.

Abstract

The mechanisms underlying neurologic deficits and delayed neuronal death after ischemia are not fully understood. In the present study, we report that transient cerebral ischemia induces accumulation of ubiquitinated proteins (ubi-proteins) in postsynaptic densities (PSDs). By immunoelectron microscopy, we demonstrated that ubi-proteins were highly accumulated in PSD structures after ischemia. On Western blots, ubi-proteins were markedly increased in purified PSDs at 30 minutes of reperfusion, and the increase persisted until cell death in the CA1 region after ischemia. In the resistant DG area, however, the changes were transient and significantly less pronounced. Deposition of ubi-proteins in PSDs after ischemia correlates well with PSD structural damage in the CA1 region as viewed by electron microscopy. These results suggest that the ubiquitin-proteasome system fails to repair and remove damaged proteins in PSDs. The changes may demolish synaptic neurotransmission, contribute to neurologic deficits, and eventually lead to delayed neuronal death after transient cerebral ischemia.

• Authors: Chen Li Liu, Maryann E Martone, Bingren R Hu
• Journal: Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism (J Cereb Blood Flow Metab) Vol. 24 Issue 11 Pg. 1219-25 (Nov 2004) ISSN: 0271-678X [Print] United States
• PMID: 15545915 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Ubiquitins

Topics

• Animals
• Brain (metabolism, ultrastructure)
• Ischemic Attack, Transient (metabolism, pathology)
• Male
• Microscopy, Electron
• Rats
• Rats, Wistar
• Synapses (metabolism, ultrastructure)
• Ubiquitins (metabolism)