Research progress on the function and regulatory pathways of amino acid permeases in fungi.

Nitrogen sources are pivotal for the formation of fungal mycelia and the biosynthesis of metabolites, playing a crucial role in the growth and development of fungi. Amino acids are integral to protein construction, constitute an essential nitrogen source for fungi. Fungi actively uptake amino acids from their surroundings, a process that necessitates the involvement of amino acid permeases (AAPs) located on the plasma membrane. By sensing the intracellular demand for amino acids and their extracellular availability, fungi activate or suppress relevant pathways to precisely regulate the genes encoding these transporters. This review aims to illustrate the function of fungal AAPs on uptake of amino acids and the effect of AAPs on fungal growth, development and virulence. Additionally, the complex mechanisms to regulate expression of aaps are elucidated in mainly Saccharomyces cerevisiae, including the Ssy1-Ptr3-Ssy5 (SPS) pathway, the Nitrogen Catabolite Repression (NCR) pathway, and the General Amino Acid Control (GAAC) pathway. However, the physiological roles of AAPs and their regulatory mechanisms in other species, particularly pathogenic fungi, merit further exploration. Gaining insights into these aspects could reveal how AAPs facilitate fungal adaptation and survival under diverse stress conditions, shedding light on their potential impact on fungal biology and pathogenicity.