Abstract
The protein p42IP4, expressed mainly in brain, specifically recognizes two second messenger molecules, Ins(1,3,4,5)P4 (IP 4), a water soluble metabolite of IP3 and the lipid PtdIns(3,4,5)P3 (PIP3), the product of the growth factor-activated enzyme PI-3-kinase. Here, we studied whether there is short-term regulation of the expression level of p42IP4 in limbic brain areas following acoustic and electric stimulation. The stimuli down-regulated the mRNA and protein levels within 2h in amygdala, hypothalamus and cingulate/retrospenial cortex. p42IP4 mRNA decreased by about 50% for about 24h, but recovered to control values after 72h. The present results are the first indication of a specific role of p42IP4 in the short-term regulation of a behavioral response. They indicate that p42 IP4, an adapter protein in PIP3-dependent cellular signaling, may play an important role in the signal transduction pathways regulating plasticity in neuronal cells.