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Membrane interaction of cyanobacterial and chloroplast ESCRT-III proteins

Mirka Kutzner1, Benedikt Junglas2, Mayank Sharma3

  • 1Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Mainz, Germany.

The Plant Journal : for Cell and Molecular Biology
|April 6, 2026
PubMed

Insights

Inner membrane protein IM30/Vipp1 binds to chloroplasts and cyanobacteria membranes, mediating vesicle formation and membrane remodeling. Its structure and function are linked to the ESCRT-III superfamily.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Organelle Biology

Background:

  • Inner membrane protein IM30 (Vipp1) identified in pea chloroplasts binds to the inner envelope membrane.
  • IM30/Vipp1 is involved in vesicle formation and membrane stabilization, similar to its bacterial homolog PspA.
  • IM30/Vipp1 and PspA belong to the ESCRT-III superfamily, known for membrane remodeling in eukaryotes.

Purpose of the Study:

  • To provide a molecular understanding of IM30/Vipp1 structure and activity in cyanobacteria and chloroplasts.
  • To discuss the membrane binding of IM30/Vipp1 in chloroplasts/cyanobacteria and contrast it with eukaryotic ESCRT-III function.
  • To explore the roles of IM30/Vipp1 in membrane remodeling, including internalizations and tubulation.

Main Methods:

  • Structural resolution of cyanobacterial IM30/Vipp1 and PspA proteins.
  • In vitro studies to understand IM30/Vipp1 structure and activity.
  • Analysis of key regions in IM30/Vipp1 mediating membrane binding and structure formation.

Main Results:

  • IM30/Vipp1 binds to chloroplast and cyanobacterial membranes.
  • Two key regions in IM30/Vipp1 mediate initial membrane binding.
  • IM30/Vipp1 forms spiral, barrel, and/or rod structures on membrane surfaces, facilitating internalizations and tubulation.

Conclusions:

  • IM30/Vipp1 plays a crucial role in membrane remodeling in chloroplasts and cyanobacteria.
  • The ESCRT-III superfamily's function in membrane remodeling extends to chloroplasts and cyanobacteria.
  • Understanding IM30/Vipp1 structure and function offers insights into organelle biogenesis and membrane dynamics.
Keywords:
ESCRT‐IIIIM30PspAVipp1chloroplastcyanobacteriamembrane dynamicsmembrane remodelingthylakoid membrane

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