Ergosterol in fungal cell membrane (Ergosterol)

Ergosterol is the primary sterol component of fungal cell membranes, analogous to cholesterol in animal cells. It is essential for maintaining membrane fluidity, integrity, and permeability, which are critical for fungal cell viability, growth, and adaptation to environmental stressors[2][3][9]. Ergosterol is synthesized in the endoplasmic reticulum and transported to the plasma membrane, where it exerts its structural and regulatory roles[2][13]. Its unique presence in fungi (absent in human cells) makes it a major target for antifungal drugs, which either bind directly to ergosterol (polyenes) or inhibit its biosynthesis (azoles, morpholines)[2][8][13]. Disruption of ergosterol homeostasis leads to impaired membrane function and fungal cell death, but mutations or altered regulation in ergosterol biosynthesis and transport can confer resistance to therapy[2][8][13].

Other names

Fungal sterolMycosteroMajor membrane sterol of fungiMain sterol of yeast and mushroomsAnalogous to cholesterol in animal cells

Polyenes (e.g., amphotericin B): Bind directly to ergosterol, causing pore formation and cell lysis[8][13] - Azoles: Inhibit ergosterol biosynthesis by targeting lanosterol 14α-demethylase (ERG11/CYP51), leading to accumulation of toxic sterol intermediates and defective membrane formation[8][13] - Morpholines: Inhibit steps in ergosterol biosynthesis (C-14 sterol reductase, C-8 sterol isomerase), resulting in abnormal sterol accumulation and membrane dysfunction[8] - Echinocandins: Inhibit cell wall synthesis (indirectly affecting membrane integrity)[8]