Nonspecific association of 2',3'-cyclic nucleotide 3'-phosphodiesterase with the rat forebrain postsynaptic density fraction.
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.
Cho
Sun-Jung
SJ
Department of Microbiology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Korea.
Jung
Jae Seob
JS
Shin
Seung Chul
SC
Jin
IngNyol
I
Ko
Bok Hyun
BH
Kim Kwon
Yunhee
Y
Suh-Kim
Haeyoung
H
Moon
Il Soo
IS
D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000378:metabolism*; D000375:Aging / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D016548:Prosencephalon / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013379:Substrate Specificity
D009419:Nerve Tissue Proteins; C033652:postsynaptic density proteins; D019000:Phosphotyrosine; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases