1. ¹Laboratory of Molecular Pathophysiology, Wayne State University School of Medicine, Detroit, MI, USA
2. ²Laboratory of Molecular Pathophysiology, National Institute of Mental Health, Bethesda, MD, USA

Correspondence: Dr G Chen, Laboratory of Molecular Pathophysiology, Bldg 49, Room B1EE16, Mood & Anxiety Disorders Program, NIMH, NIH, Bethesda, MD 20892, USA. Tel: +1 301 451 8425; Fax: +1 301 480 0123; E-mail: cheng@intra.nimh,nih.gov

Received 16 July 2002; Revised 5 November 2002; Accepted 12 November 2002; Published online 12 March 2003.

Abstract

Post-mortem brain tissue provides a unique opportunity to uncover the genes or proteins involved in the pathophysiology of neuropsychiatric disorders. Protein phosphorylation is a common protein modification within intracellular signaling pathways that affects the distribution and function of protein, and has been hypothesized to be of major importance in both the pathophysiology and treatment of major neuropsychiatric disorders. Thus, we were interested in ascertaining the stability of the phosphorylated forms of proteins that are involved in cellular signaling. Antibodies against phospho-tyrosine, phospho-threonine, and phospho-PKA substrates were used to examine the PMI effects on the general amounts of proteins in their phosphorylated form. Phospho-specific antibodies for ERK, JNK, RSK, CREB, and ATF-2 were used to test the effects of PMI on specific proteins whose functioning are known to be regulated markedly by phosphorylation. We found that PMI rapidly decreased the levels of proteins in their phosphorylated states and also decreased the total levels of certain proteins. The PMI effects were observed in the samples stored at both 4°C and room temperature, in both frontal cortex and hippocampus. Thus, it appears that measurements (such as two-dimensional gel electrophoresis and functional assays) that rely on the phosphorylation state of proteins would be extremely sensitive to PMI.