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Nat Chem Biol. 2014 Dec;10(12):1034-42. doi: 10.1038/nchembio.1662. Epub 2014 Oct 26.

Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas.

Author information

1
Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California, USA.
2
1] Department of Chemistry, University of California-Berkeley, Berkeley, California, USA. [2] Howard Hughes Medical Institute, University of California-Berkeley, Berkeley, California, USA.
3
Department of Pharmaceutical Sciences, Wayne State University, Detroit, Michigan, USA.
4
Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, California, USA.
5
1] Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California, USA. [2] Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, California, USA. [3] Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, USA.
6
Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, USA.
7
1] Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California, USA. [2] Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, USA.

Abstract

We identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu(+) accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotope labeling demonstrated that sequestered Cu(+) became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.

Comment in

PMID:
25344811
PMCID:
PMC4232477
DOI:
10.1038/nchembio.1662
[Indexed for MEDLINE]
Free PMC Article

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