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Deciphering the Molecular Mechanism and Function of Pore-Forming Toxins Using Leishmania major
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Fungal MACPF-like proteins and aegerolysins: bi-component pore-forming proteins?

Katja Ota1, Matej Butala, Gabriella Viero

  • 1Department of Biology Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000, Ljubljana, Slovenia.

Sub-Cellular Biochemistry
|May 7, 2014
PubMed

Insights

Fungal proteins, pleurotolysin B (MACPF domain) and aegerolysins, form pores in cholesterol-rich membranes. This two-component system causes cell lysis, impacting fungal lifestyle.

Area of Science:

  • Biochemistry
  • Mycology
  • Structural Biology

Background:

  • Membrane-attack complex/perforin (MACPF) domain proteins are widespread with diverse roles.
  • In fungi, MACPF proteins and aegerolysins are found in specific lineages and may function together.
  • Pleurotolysin B (MACPF) and aegerolysin-like proteins (pleurotolysin A, ostreolysin A) from oyster mushrooms are key examples.

Purpose of the Study:

  • To investigate the mechanism of pore formation by fungal MACPF and aegerolysin proteins.
  • To elucidate the structural basis of their interaction with lipid membranes.
  • To understand the biological significance of this protein system in fungi.

Main Methods:

  • Purification of pleurotolysin A and ostreolysin A from Pleurotus ostreatus.
  • Biochemical assays to determine membrane interaction and pore formation.
  • Electron microscopy to visualize the protein complex structure.

Main Results:

  • Aegerolysin-like proteins confer selectivity for cholesterol- and sphingomyelin-rich membranes.
  • Oligomerized pleurotolysin B molecules are recruited to form a 13-meric rosette-like pore complex.
  • The pore (~4-5 nm lumen diameter) is non-selectively permeable, leading to colloid-osmotic lysis.

Conclusions:

  • Fungal MACPF and aegerolysin proteins form a novel bi-component pore-forming system.
  • This system is crucial for fungal defense or attack mechanisms.
  • The study provides structural insights into fungal cytolytic mechanisms.

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