Fear conditioning is associated with altered integration of PLC and ERK signaling in the hippocampus

• Published in: Pharmacology, biochemistry and behavior biochemistry and behavior, 2004-12, Vol.79 (4), p.633-640
• Main Authors: Buckley, Colin T., Caldwell, Kevin K.
• Format: Article
• Language: English
• Subjects: Animal; Animals; Biological and medical sciences; Conditioning; Conditioning (Psychology) - physiology; Docking; Extracellular Signal-Regulated MAP Kinases - physiology; Fear - physiology; Fear conditioning; Female; Fundamental and applied biological sciences. Psychology; Hippocampal formation; Hippocampus - enzymology; Hippocampus - physiology; Isoenzymes - metabolism; Isoenzymes - physiology; Learning. Memory; MAP Kinase Signaling System - physiology; MAPK; Mitogen-Activated Protein Kinase 1 - physiology; Mitogen-Activated Protein Kinase 3 - physiology; Phospholipase C beta; Phospholipase C gamma; PLC; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Sprague-Dawley; Type C Phospholipases - metabolism; Type C Phospholipases - physiology
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/j.pbb.2004.09.013

The extracellular signal-regulated protein kinases (ERKs) are proline-directed, serine/threonine kinases that regulate a variety of cellular functions, including proliferation, differentiation, and plasticity. In the present report, we provide evidence that ERK2 and phosphatidylinositol-specific phospholipase C (PLC)-β and -γ isozymes interact in the rat hippocampal formation. We found that anti-PLC-β1a, -β2, -β4, -γ1 and -γ2, but not -β3, immune complexes isolated from rat hippocampal formation postnuclear fractions contain anti-ERK2 immunoreactivity. Further, we show that PLC catalytic activity is associated with anti-ERK2 immunoprecipitates isolated from the hippocampal formation, and that the amount of enzyme activity is significantly increased following fear-conditioned learning. The observed interactions may be mediated by consensus sequences conforming to an ERK2 docking site, termed a D-domain, that we identified in PLC-β1a, -β2, -β4 -γ1 and -γ2. Based on these results, we propose that PLC-β and PLC-γ isozymes form signaling complexes with ERK2 in rat brain, and these complexes play critical roles in learning and memory, as well as a variety of other neuronal functions.