Pim kinase expression is induced by LTP stimulation and required for the consolidation of enduring LTP

In animals and several cellular models of synaptic plasticity, long-lasting changes in synaptic strength are dependent on gene transcription and trans lation. Here we demonstrate that Pim-l, a serine/threonine kinase closely r elated to Pim-2 and Pim-3, is induced in hippocampus in response to stimuli that evoke longterm potentiation (LTP), Mice deficient for Pim-l show norm al synaptic transmission and short-term plasticity, How ever, they fail to consolidate enduring LTP even though Pim-2 and Pim-3 are constitutively exp ressed in the hippocampus and Pim-3 expression is similarly induced by syna ptic activity, Thus, expression of Pim-l is required for LTP, Its level of expression and, consequently, its capacity to phosphorylate target proteins in dendritic and nuclear compartments of stimulated neurons might be a det ermining factor for the establishment of long-lasting changes in synaptic s trength.