Role of proteolysis in copper homoeostasis.
The cop operon of Enterococcus hirae controls cytoplasmic copper levels. It encodes two copper ATPases, a repressor, and the CopZ metallochaperone. Transcription of these genes is induced by copper. However, at higher copper concentrations, CopZ is degraded by a copper-activated proteolytic activity. This specific proteolysis of CopZ can also be demonstrated in vitro with E. hirae extracts. Growth of the cells in copper increases the copper-inducible proteolytic activity in extracts. Zymography reveals the presence of a copper-dependent protease in crude cell lysates. Copper-stimulated proteolysis of CopZ appears to play an important role in copper homoeostasis by E. hirae.
Department of Clinical Pharmacology, University of Berne, Murtenstrasse 35, 3010 Berne, Switzerland. marc.solioz@ikp.unibe.ch
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D001426:Bacterial Proteins / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D016983:Enterococcus / Q000378:metabolism*; D006706:Homeostasis; D018832:Molecular Chaperones / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism
D001426:Bacterial Proteins; C092379:CopZ protein, Enterococcus hirae; D018832:Molecular Chaperones; D015534:Trans-Activators; D003300:Copper