The Candida albicans CTR1 gene encodes a functional copper transporter

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Copper and iron uptake are interconnected in Saccharomyces cerevisiae via a high-affinity reductive system.
• Similar mechanisms are suspected to operate in Candida albicans, a significant human pathogen.

Purpose of the Study:

• To identify and characterize the Candida albicans gene responsible for high-affinity copper uptake.
• To investigate the functional and regulatory aspects of this gene in both C. albicans and S. cerevisiae.

Main Methods:

• Gene identification and functional complementation of a Saccharomyces cerevisiae mutant.
• Sequence analysis of the Candida albicans CTR1 (CaCTR1) gene and its protein product (Ctr1p).
• Analysis of CaCTR1 transcriptional regulation in response to copper and characterization of a C. albicans ctr1-null mutant.

Main Results:

• The CaCTR1 gene was identified and shown to rescue copper uptake defects in S. cerevisiae.
• CaCTR1 encodes a protein (Ctr1p) with structural similarities to S. cerevisiae Ctr1p, including putative copper-binding motifs and transmembrane regions.
• CaCTR1 is transcriptionally regulated by copper availability in both species, potentially involving a Mac1p-like regulator in C. albicans.
• A C. albicans ctr1-null mutant exhibited impaired copper uptake, leading to growth defects, respiratory deficiency, oxidative stress sensitivity, and morphological changes.

Conclusions:

• CaCTR1 is essential for high-affinity copper transport in Candida albicans.
• The findings suggest a conserved role and regulatory mechanism for CTR1 homologs in copper homeostasis between S. cerevisiae and C. albicans.
• CaCTR1 may be regulated by a Mac1p-like transactivator in C. albicans, similar to its S. cerevisiae counterpart.