Assembling microtubules disintegrate the postsynaptic density in vitro

Abstract

The postsynaptic density (PSD), a disk-shaped protein aggregation of several hundred nm in diameter, plays important roles in the signal transduction and molecular organization of the excitatory synapses in mammalian CNS. The PSD resides in the microfilament-enriched cytoplasm of dendritic spines where the transient appearance of microtubules has been reported. When PSD isolated from porcine brain was incubated with polymerizing a,b-tubulins, its turbidity became greater than that of the original PSD, suggesting that the PSD's structure was altered upon incubating with assembling microtubules. By transmission electron microscopy, smaller PSD fragments and several novel structures, including holes and fingerlike extensions, were found in the PSD after incubation with assembling microtubules, but not in the original PSD or in the PSD incubated with a,b-tubulins pretreated with vincristine. The results suggest that the interactions with assembling microtubules may result in the formation of holes in the PSD, and the rupture of these holes subsequently leads to the formation of smaller PSD fragments. Cell Motil. Cytoskeleton 64: 6-18, 2007. '

Effects of Acanthopanax senticosus on Brain Injury Induced by Simulated Spatial Radiation in Mouse Model Based on Pharmacokinetics and Comparative Proteomics

“…α-Tubulin could also cooperate with actin proteins to regulate thyroid hormone signaling pathway. The proteomic analysis shows that radiation damage caused a decrease in α-tubulin expression, leading to tubulin polymerization and developmental abnormalities, suggesting that the neuronal synaptic function in the central nervous system (CNS) of irradiated mouse was influenced, nerve cell signaling pathways blocked, and that locomotion proteins and axoplasmic flow, which are maintained by α-tubulin, were damaged, and that nerve cells’ normal activities, which depend on synaptic terminals, were affected [ 28 ]. The content of β-tubulin protein was also significantly different in PFC of irradiated mouse.…”