title: Biogenesis and proteolytic processing of lysosomal DNase II.
abstract: Deoxyribonuclease II (DNase II) is a key enzyme in the phagocytic digestion of DNA from apoptotic nuclei. To understand the molecular properties of DNase II, particularly the processing, we prepared a polyclonal antibody against carboxyl-terminal sequences of mouse DNase II. In the present study, partial purification of DNase II using Con A Sepharose enabled the detection of endogenous DNase II by Western blotting. It was interesting that two forms of endogenous DNase II were detected--a 30 kDa form and a 23 kDa form. Neither of those forms carried the expected molecular weight of 45 kDa. Subcellular fractionation showed that the 23 kDa and 30 kDa proteins were localized in lysosomes. The processing of DNase II in vivo was also greatly altered in the liver of mice lacking cathepsin L. DNase II that was extracellularly secreted from cells overexpressing DNase II was detected as a pro-form, which was activated under acidic conditions. These results indicate that DNase II is processed and activated in lysosomes, while cathepsin L is involved in the processing of the enzyme.
authors.affiliation: Department of Cell Biology and Neuroscience, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Ohkouchi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shibata
authors.forename: Mitsuho
authors.initials: M
authors.lastname: Sasaki
authors.forename: Masato
authors.initials: M
authors.lastname: Koike
authors.forename: Paul
authors.initials: P
authors.lastname: Safig
authors.forename: Christoph
authors.initials: C
authors.lastname: Peters
authors.forename: Shigekazu
authors.initials: S
authors.lastname: Nagata
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Uchiyama
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli; D006801:Humans; D008247:Lysosomes / Q000201:enzymology*; D051379:Mice; D001678:Organelle Biogenesis; D016133:Polymerase Chain Reaction; D059748:Proteolysis
chemical_list: D004706:Endodeoxyribonucleases; C019329:deoxyribonuclease II