Serum-induced expression of metallothionein isoforms in K-562 cells.
The metallothionein (MT) expression was studied in the hematopoietic precursor cell line K-562, after serum deprivation and reconstitution of the cells in medium with 10% (v/v) FCS. Serum deprivation for 72 h markedly downregulated the MT mRNA expression, only the isoforms most abundant in normal K-562 cells were clearly detectable. Within 1-1.5 h after serum supplementation however, a definite induction of MT mRNA was noticed, and all isoforms were induced. Forty-eight hours after serum stimulation, the MT mRNA expression of all isoforms decreased again. Also MT protein levels increased twofold 24 h after serum stimulation. These results suggest that MT has a function in the re-entry of resting cells into the cell cycle, this function however could not be assigned to a specific MT isoform. The induction of MT after serum stimulation was independent of protein synthesis, but dependent on phosphorylation.
Kuppens
Kelly
K
Laboratory for Biochemistry, Department of Chemistry, Katholieke Universiteit Leuven, Belgium.
De Ley
Marc
M
D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D020014:K562 Cells; D008668:Metallothionein / Q000235:genetics* / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044967:Serum / Q000502:physiology*; D015032:Zinc / Q000494:pharmacology
D020033:Protein Isoforms; D012333:RNA, Messenger; D008668:Metallothionein; D003513:Cycloheximide; D015032:Zinc