HIGH EXTERNAL POTASSIUM INDUCES AN INCREASE IN THE PHOSPHORYLATION OFTHE CYTOSKELETAL PROTEIN MAP2 IN RAT HIPPOCAMPAL SLICES

Depolarization induced in rat hippocampal slices by a high concentrati on of extracellular K+ leads to an increase in the phosphorylation of microtubule-associated protein MAP2. The comparison of the major phosp hopeptides derived from in situ and in vitro phosphorylated MAP2 sugge sts the implication of calcium-dependent protein kinases, including ca lcium/calmodulin-dependent protein kinase type II and protein kinase C , in the up-phosphorylation of MAP2. In particular, a peptide containi ng the tubulin-binding domain of the MAP2 molecule may be phosphorylat ed by protein kinase C. As the association of MAP2 with the cytoskelet on may be regulated by phosphorylation, we suggest that changes in the phosphorylation level of MAP2 might be involved in synaptic remodelli ng in hippocampal neurons.