Copper-Induced Stimulation of Ectophosphatase Activity of Candida albicans

Candida albicans is an opportunistic fungal pathogen that can cause superficial and life-threatening infections, particularly in immunocompromised individuals. Its ability to adhere to host cells is critical for colonization and infection. In this context, investigating ectophosphatases is particularly relevant, as these enzymes have been associated with fungal adhesion to host cells. This study aimed to investigate the nature of copper-induced stimulation of ectophosphatase activity in C. albicans. Ectophosphatase activity was measured using p-nitrophenyl phosphate as substrate. Micromolar concentrations of CuCl₂ markedly stimulated ectophosphatase activity, and its response to reducing agents and metal chelators suggested that this modulation does not involve redox reactions. The significant differences between the biochemical properties of basal (Cu²⁺-independent) and Cu²⁺-dependent ectophosphatase activities suggest the presence of at least two distinct ectophosphatases in C. albicans. Cu²⁺-independent ectophosphatase activity presented an acidic profile and was insensitive to Mg²⁺, whereas Cu²⁺-dependent ectophosphatase activity exhibited an alkaline profile and was also stimulated by Mg²⁺. Both activities were negatively modulated by classical phosphatase inhibitors, but Cu²⁺-dependent ectophosphatase had lower sensitivity compared to the basal activity. These findings highlight the role of copper as a modulator of C. albicans ectophosphatase activity and suggest potential implications for fungal adaptation during infection.