Fungal cell membrane lipids and cell envelope

The fungal cell membrane and cell envelope are critical structural components that distinguish fungi from mammalian cells, making them primary targets for antifungal therapy. The fungal cell membrane is characterized by the presence of ergosterol, a sterol that maintains membrane fluidity and integrity, whereas the cell envelope (or cell wall) consists of a complex matrix of polysaccharides, including beta-glucans and chitin [StatPearls: Antifungal Antibiotics, 2023]. These structures provide essential protection against osmotic pressure and environmental stress while facilitating nutrient transport and cell signaling [Journal of Fungi, 2017]. Drugs targeting these components, such as polyenes, bind directly to ergosterol to create lethal pores, while azoles and echinocandins inhibit the biosynthesis of membrane lipids and wall polysaccharides, respectively [Nature Reviews Microbiology, 2017]. Disruption of these barriers leads to cell lysis or growth inhibition, providing a selective mechanism to treat systemic and superficial fungal infections [Microbiology and Molecular Biology Reviews, 2001]. However, the emergence of resistance and the potential for off-target effects, such as polyene-induced nephrotoxicity due to cross-reactivity with human cholesterol, remain significant clinical challenges [Clinical Microbiology Reviews, 2019]. Because this target definition encompasses both the lipid bilayer and the external polysaccharide wall, it represents a composite of several distinct molecular targets including ergosterol, 1,3-beta-glucan synthase, and chitin synthase.

Other names

Fungal cell wallFungal plasma membraneFungal cell boundaryFungal cell surface

Mechanisms include direct binding to membrane ergosterol to form ion channels (polyenes), inhibition of ergosterol biosynthesis via 14-alpha-demethylase (azoles) or squalene epoxidase (allylamines), and non-competitive inhibition of 1,3-beta-D-glucan synthase (echinocandins).