1,3-beta-glucan synthase (Fks1) (Fks1)

1,3-beta-glucan synthase (Fks1) is a large, integral membrane glycosyltransferase enzyme found in fungi and some bacteria, responsible for synthesizing β-1,3-glucan—a primary structural component of the fungal cell wall[2][3][4][6][7]. The enzyme complex consists of the catalytic Fks1 subunit and regulators (e.g., Rho1 GTPase), and resides in the plasma membrane[3]. It catalyzes the polymerization of glucose from UDP-glucose into β-1,3-glucan. Fks1 is essential for fungal cell wall integrity, growth, and viability, and is the molecular target of echinocandin class antifungal drugs and the triterpenoid ibrexafungerp[2][6]. These drugs inhibit Fks1, causing cell wall disruption and cell death. Resistance to these drugs is mainly due to amino acid substitutions in Fks1[7]. Fks1 is classified as a GT-C family member based on its membrane integration and catalytic domain structure[4]. There is no direct therapeutic target known as \"microbial membrane phospholipids\"—phospholipids are broad membrane constituents, not specific drug targets in the same sense as glucan synthase enzymes.

Other names

β-1,3-glucan synthaseβ-glucan synthaseGS complexFks1p

Inhibition of β-1,3-glucan synthase blocks the synthesis of β-1,3-glucan, leading to fungal cell wall weakening and cell death