title: Apo-metallothionein emerging as a major player in the cellular activities of metallothionein.
abstract: Observations of apo-metallothionein (apo-MT) have been made under a variety of physiologic circumstances, including zinc deficiency in cell culture and in rodents, cellular induction of MT by dexamethasone with concurrent Zn deficiency, a variety of tumors under normal Zn conditions, MT induction by Zn and Bi citrate, induction of hepatic MT after tumor cell injection into nude mice, and overexpression of cardiac MT in MT transgenic mice. Experiments demonstrating both the lability of Zn and Cu bound to MT and the cellular stability of apo-MT are described to help rationalize the widespread presence of this metal-depleted species. Finally, comparative in vitro and cellular experiments examined the relative reactivity of Zn- and apo-MT with nitric oxide species, showing that apo-MT is much more reactive chemically and that in cells it may be a principal reactive species within the MT pool.
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA. petering@uwm.edu
authors.forename: David H
authors.initials: DH
authors.lastname: Petering
authors.forename: Jianyu
authors.initials: J
authors.lastname: Zhu
authors.forename: Susan
authors.initials: S
authors.lastname: Krezoski
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Meeusen
authors.forename: Christy
authors.initials: C
authors.lastname: Kiekenbush
authors.forename: Sara
authors.initials: S
authors.lastname: Krull
authors.forename: Todd
authors.initials: T
authors.lastname: Specher
authors.forename: Munira
authors.initials: M
authors.lastname: Dughish
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology; D005029:Ethylenediamines / Q000494:pharmacology; D008668:Metallothionein / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008819:Mice, Nude; D008822:Mice, Transgenic; D009206:Myocardium / Q000378:metabolism; D009368:Neoplasm Transplantation; D015032:Zinc / Q000172:deficiency
chemical_list: D005029:Ethylenediamines; D003907:Dexamethasone; D008668:Metallothionein; D015032:Zinc; C044387:N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine