2',3'-CYCLIC NUCLEOTIDE 3'-PHOSPHODIESTERASE IS ASSOCIATED WITH MITOCHONDRIA IN DIVERSE ADRENAL-CELL TYPES

In this study, we have examined the expression and intracellular local isation of the myelin protein 2',3'-cyclic nucleotide 3'-phosphodieste rase (CNP) in bovine adrenal medullary chromaffin cell cultures. By im munoblotting, using two distinct anti-CNP monoclonal antibodies, CNP w as detected in medullary cell cultures and expression of CNP was confi rmed by reverse transcription and PCR amplification, CNP did not leak from digitonin-permeabilised chromaffin cells, suggesting that there i s no cytosolic pool of this protein. Immunofluorescence studies with b oth antibodies showed that all cells in the medullary chromaffin cell culture were stained with a punctate appearance consistent with an int racellular localisation for CNP. More specifically it was demonstrated that CNP is colocalised with mitochondria, Various cell types in chro maffin cell cultures were stained with a mitochondrial pattern and CNP staining was co-localised with mitochondrial staining, These results show that CNP is a widely expressed protein that is associated with mi tochondria and provides new clues as to its cellular function outside of myelin structures.