title: Distribution of prolyl oligopeptidase in the mouse whole-body sections and peripheral tissues.
abstract: Prolyl oligopeptidase (POP) is a serine endopeptidase that hydrolyses proline-containing peptides shorter than 30-mer, including many bioactive peptides. The distribution of POP in the brain has been studied but little is known about the distribution of peripheral POP. We used immunohistochemistry to localize POP in mouse whole-body sections and at the cellular level in peripheral tissues. Furthermore, we used a POP activity assay to reveal the associations between POP protein and its enzymatic activity. The highest POP protein densities were found in brain, kidney, testis and thymus, but in the liver the amounts of POP protein were small. There were remarkable differences between the distribution of POP protein and activity. The highest POP activities were found in the liver and testis while kidney had the lowest activity. In peripheral tissues, POP was present in various cell types both in the cytoplasm and nucleus of the cells, in contrast to the brain where no nuclear localization was detected. These findings support the proposed role of POP in cell proliferation in peripheral tissues. The dissociation of the distribution of POP protein and its enzymatic activity points to nonhydrolytic functions of POP and to strict endogenous regulation of POP activity.
authors.affiliation: Department of Pharmacology and Toxicology, University of Kuopio, P.O. Box 1627, 70211, Kuopio, Finland. Timo.Myohanen@uku.fi
authors.forename: Timo T
authors.initials: TT
authors.lastname: Myöhänen
authors.forename: Jarkko I
authors.initials: JI
authors.lastname: Venäläinen
authors.forename: J Arturo
authors.initials: JA
authors.lastname: García-Horsman
authors.forename: Marjo
authors.initials: M
authors.lastname: Piltonen
authors.forename: Pekka T
authors.initials: PT
authors.lastname: Männistö
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology; D002467:Cell Nucleus / Q000201:enzymology; D049109:Cell Proliferation; D003593:Cytoplasm / Q000201:enzymology; D005455:Fluorescent Antibody Technique; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D051379:Mice; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases / Q000032:analysis*; D013737:Testis / Q000201:enzymology; D013950:Thymus Gland / Q000201:enzymology
chemical_list: D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases