Plasma Membrane ATPase Function in Fungi and Plants

In fungi and plants, plasma membrane P-type H⁺-ATPases are vital enzymes that transduce the energy of ATP hydrolysis into an electrochemical proton gradient across the cell surface. This proton motive force energises secondary transport processes, supports cytosolic pH homeostasis and generates membrane potential. In fungal cells, the archetypal Pma1 enzyme assembles into autoinhibited hexamers, with a C-terminal regulatory helix locking adjacent subunits until specific phosphorylation events trigger activation. Plant plasma membrane H⁺-ATPases share the same fundamental mechanism but are monomeric and regulated by phosphorylation of a penultimate threonine followed by binding of 14-3-3 proteins. Tight control of pump activity underpins nutrient uptake, cell expansion, response to osmotic and ionic stresses, stomatal function and integration with central growth pathways such as TORC1. Recent structural, genetic and biochemical advances have elucidated the molecular basis of autoinhibition, lipid interactions and regulatory networks, offering opportunities for targeted manipulation in agriculture and antifungal therapy.

Research from Nature Portfolio

Recent cryo-electron microscopy studies have determined the high-resolution structure of the native fungal Pma1 hexamer embedded in its lipid environment. The work reveals that six Pma1 protomers encircle a liquid-crystalline lipid patch, forming a specialised membrane compartment. In the autoinhibited state at neutral pH, a C-terminal α-helix bridges the phosphorylation domains of neighbouring subunits, preventing catalytic turnover. Acidification induces displacement of this helix, accompanied by a downward shift and rotation of transmembrane helices that create a continuous proton translocation pathway. These findings establish a detailed mechanistic model for pH-triggered activation and provide a structural platform for design of inhibitors that exploit unique oligomer interfaces.

Plasma Membrane ATPase Function in Fungi and Plants publication trend

The graph below shows the total number of articles in plasma membrane atpase function in fungi and plants across all publications each year (not limited to Nature Index journals).

Technical terms

P-type ATPase: A membrane enzyme family that forms a transient phosphorylated intermediate during ATP-driven transport of ions across biological membranes.

Autoinhibitory domain: A regulatory C-terminal segment whose interaction with the core enzyme imposes an inactive conformation until specific signals cause its release.

Hexameric assembly: Six identical subunits organised into a ring-like complex, forming a stable membrane microdomain and enabling coordinated activation.

Proton-motive force: The electrochemical gradient of protons across a membrane that provides energy for transport of nutrients and other metabolites.

14-3-3 proteins: Regulatory scaffold molecules in plants that bind phosphorylated target proteins, such as H⁺-ATPases, stabilising their active conformation.

References

1. Phosphoregulation of the yeast Pma1 H+-ATPase autoinhibitory domain involves the Ptk1/2 kinases and the Glc7 PP1 phosphatase and is under TORC1 control.. PLOS Genetics (2024).
2. Structure, function and biogenesis of the fungal proton pump Pma1. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research (2023).
3. Fungal Plasma Membrane H+-ATPase: Structure, Mechanism, and Drug Discovery. Journal of Fungi (2024).
4. Structure and activation mechanism of the hexameric plasma membrane H+-ATPase. Nature Communications (2021).
5. Structure of the hexameric fungal plasma membrane proton pump in its autoinhibited state. Science Advances (2021).