Mechanisms of RCD-1 pore formation and membrane bending

Area of Science:

• Cell biology
• Molecular mechanisms of cell death
• Fungal protein interactions

Background:

• Regulator of cell death-1 (RCD-1) controls fungal cell death and prevents cytoplasmic mixing.
• RCD-1 comprises RCD-1-1 and RCD-1-2, fungal gasdermin (GSDM)-like proteins.
• The precise mechanism of RCD-1's membrane interaction was previously unknown.

Purpose of the Study:

• To elucidate the molecular mechanisms by which RCD-1 interacts with and affects cell membranes.
• To investigate the structural assembly and membrane-disrupting capabilities of RCD-1 proteins.

Main Methods:

• Atomic force microscopy (AFM) for imaging and force spectroscopy.
• AlphaFold for protein structure prediction.
• Micropipette aspiration to assess membrane mechanics.

Main Results:

• RCD-1 proteins bind to acidic lipid membranes.
• RCD-1-1 and RCD-1-2 form heterodimers that assemble into transmembrane pores (~14.5 nm width).
• RCD-1 proteins induce significant membrane bending, particularly in membranes with low bending moduli.

Conclusions:

• RCD-1 mediates cell death through pore formation and membrane deformation.
• These actions are crucial for preventing cytoplasmic mixing and protecting fungal cells.
• The pore formation and membrane bending mechanism may be conserved across the GSDM family.