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Mol Cell. 2017 Jan 19;65(2):207-219. doi: 10.1016/j.molcel.2016.12.008.

Programmed Ribosomal Frameshifting Generates a Copper Transporter and a Copper Chaperone from the Same Gene.

Author information

1
Center for Biomolecular Sciences-m/c 870, University of Illinois at Chicago, 900 S. Ashland Avenue, Chicago, IL 60607, USA.
2
Proteomics Center of Excellence, Northwestern University, 633 Clark Street, Chicago, IL 60208, USA.
3
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
4
Center for Biomolecular Sciences-m/c 870, University of Illinois at Chicago, 900 S. Ashland Avenue, Chicago, IL 60607, USA. Electronic address: nvazquez@uic.edu.
5
Center for Biomolecular Sciences-m/c 870, University of Illinois at Chicago, 900 S. Ashland Avenue, Chicago, IL 60607, USA. Electronic address: shura@uic.edu.

Abstract

Metal efflux pumps maintain ion homeostasis in the cell. The functions of the transporters are often supported by chaperone proteins, which scavenge the metal ions from the cytoplasm. Although the copper ion transporter CopA has been known in Escherichia coli, no gene for its chaperone had been identified. We show that the CopA chaperone is expressed in E. coli from the same gene that encodes the transporter. Some ribosomes translating copA undergo programmed frameshifting, terminate translation in the -1 frame, and generate the 70 aa-long polypeptide CopA(Z), which helps cells survive toxic copper concentrations. The high efficiency of frameshifting is achieved by the combined stimulatory action of a "slippery" sequence, an mRNA pseudoknot, and the CopA nascent chain. Similar mRNA elements are not only found in the copA genes of other bacteria but are also present in ATP7B, the human homolog of copA, and direct ribosomal frameshifting in vivo.

KEYWORDS:

copA; nascent peptide; pseudoknot; recoding; ribosome profiling; slippery sequence; translation regulation

PMID:
28107647
PMCID:
PMC5270581
DOI:
10.1016/j.molcel.2016.12.008
[Indexed for MEDLINE]
Free PMC Article

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