Figure 3.

Distribution of eIF2α kinases in various fractions obtained from cortex and hippocampus. Adult naive rats were killed, GC and hippocampus tissues were dissected, and subcellular fractionation was performed as described in Materials and Methods. Representative immunoblots of the eIF2α kinases known to be present in the brain (PKR, GCN2, and PERK). eIF2α and its three kinases are abundantly present in the light membrane (P3) fraction; however, both eIF2α and PKR are also expressed in relative high amounts in the cytosolic fraction (S3). Representative immunoblots of known synaptic and plasticity markers are shown (n = 4). Synaptic protein PSD-95 is abundantly observed in crude synaptosomal (P2) and synaptosomal membrane fractions (LP1).