Exp Mol Med.  2003 Dec;35(6):486-493.

Nonspecific association of 2',3'-cyclic nucleotide 3'-phosphodiesterase with the rat forebrain postsynaptic density fraction

• Cho SJ
• Jung JS
• Shin SC
• Jin IN
• Ko BH
• Kim Kwon Y
• Suh-Kim H
• Moon IS

Abstract

The 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP), a protein of unknown function in vivo, is abundantly expressed in myelinating glia in two isoforms, CNP1 and CNP2. In this study, immunoblot analysis showed that CNP1 is the major isoform in adult forebrain, and that both isoforms are included in the postsynaptic density (PSD) fraction and tyrosine-phosphorylated at the basal level. However, subcellular distribution and detergent extraction data showed that CNP is nonspecifically associated with the PSD fraction. Immunocytochemistry revealed that CNP is detected, in a weak but punctate pattern, in dissociated rat hippocampal neurons of 3 days to 2 weeks in vitro. The CNP-positive punctae were distributed throughout soma and dendrites, and distinct from PSD95-positive ones. Immunoblot analysis indicated that CNP is also expressed in neuronal stem cell lines, HiB5 and F11. Interestingly, in addition to the known two isoforms, a new CNP isoform of MW 45 kDa was expressed in these cell lines and was the major type of isoform in F11 cells. Taken together, our data suggest that CNP is expressed in the early stage of in vitro development and nonspecifically included in the adult rat PSD fraction.

Keyword

CNP; hippocampal cell; postsynaptic density fraction

MeSH Terms

2',3'-Cyclic-Nucleotide Phosphodiesterases/*metabolism
Aging/physiology
Animals
Cells, Cultured
Hippocampus/cytology/metabolism
Immunohistochemistry
Nerve Tissue Proteins/*metabolism
Neurons/metabolism
Phosphotyrosine/metabolism
Prosencephalon/cytology/*metabolism
Rats
Rats, Sprague-Dawley
Substrate Specificity