title: Dissecting the Process of Activation of Cancer-promoting Zinc-requiring Ectoenzymes by Zinc Metalation Mediated by ZNT Transporters.
abstract: Zinc-requiring ectoenzymes, including both secreted and membrane-bound enzymes, are considered to capture zinc in their active site for their activation in the early secretory pathway. This idea has been confirmed by our studies conducted using tissue-nonspecific alkaline phosphatase (TNAP), which is elaborately activated by means of a two-step mechanism by zinc transporter 5 (ZNT5)-ZNT6 heterodimers and ZNT7 homodimers, through protein stabilization followed by enzyme activation with zinc in the early secretory pathway. However, the molecular basis of the activation process in other zinc-requiring ectoenzymes remains largely unknown. In this study, we investigated this activation process by using three cancer-promoting zinc-requiring ectoenzymes, autotaxin (ATX), matrix metalloproteinase 9 (MMP9), and carbonic anhydrase IX (CAIX), and the chicken DT40 cell mutants that we generated; we specifically focused on clarifying whether the same or a similar activation mechanism operates in these ectoenzymes. ATX activation required ZNT5-ZNT6 heterodimers and ZNT7 homodimers in a manner similar to TNAP activation, although the protein stability of ATX was differently regulated from that of TNAP. MMP9 required ZNT5-ZNT6 heterodimers and ZNT7 homodimers for its activation as well as secretion; MMP9 was not secreted into the spent medium unless both zinc-transport complexes were present. Finally, CAIX activation by zinc was mediated not only by ZNT5-ZNT6 heterodimers and ZNT7 homodimers but also by ZNT4 homodimers; thus, these three zinc-transport complexes redundantly contribute to CAIX activation. Our results provide pivotal insights into the activation processes of zinc-requiring ectoenzymes, and furthermore, they offer novel insights for potential cancer therapy applications given the cancer-promoting potencies of ATX, MMP9, and CAIX.
authors.affiliation: From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Tokuji
authors.initials: T
authors.lastname: Tsuji
authors.affiliation: From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Kurokawa
authors.affiliation: Inserm, U1065, Centre Méditerranéen de Médecine Moléculaire (C3M), Équipe Contrôle Métabolique des Morts Cellulaires, Équipe 3, 06204 Nice, France.
authors.forename: Johanna
authors.initials: J
authors.lastname: Chiche
authors.affiliation: the Institute of Research on Cancer and Aging, University of Nice-Sophia Antipolis, Centre A. Lacassagne, 06189 Nice, France.|the Department of Medical Biology, Centre Scientifique de Monaco, MC 98000, Monaco, and.
authors.forename: Jacques
authors.initials: J
authors.lastname: Pouysségur
authors.affiliation: the Department of Molecular Virology and Oncology, Cancer Research Institute, Kanazawa University, Kanazawa 920-1192, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sato
authors.affiliation: From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Hideya
authors.initials: H
authors.lastname: Fukuzawa
authors.affiliation: From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Nagao
authors.affiliation: From the Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan, kambe1@kais.kyoto-u.ac.jp.
authors.forename: Taiho
authors.initials: T
authors.lastname: Kambe
mesh_terms: D000818:Animals; D000071231:Carbonic Anhydrase IX / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D002645:Chickens; D019281:Dimerization; D004789:Enzyme Activation; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009369:Neoplasms / Q000201:enzymology*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism*
chemical_list: D027682:Cation Transport Proteins; D010727:Phosphoric Diester Hydrolases; D020780:Matrix Metalloproteinase 9; D000071231:Carbonic Anhydrase IX; D015032:Zinc
keywords: cancer; enzyme; membrane protein; transporter; zinc