The mitochondrial inner membrane protein LETM1 modulates cristae organization through its LETM domain

Seiko Nakamura, Aiko Matsui, Shiori Akabane, Yasushi Tamura, Azumi Hatano, Yuriko Miyano, Hiroshi Omote, Mizuho Kajikawa, Katsumi Maenaka, Yoshinori Moriyama, Toshiya Endo, Toshihiko Oka

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Abstract

LETM1 is a mitochondrial inner membrane protein that is required for maintaining the mitochondrial morphology and cristae structures, and regulates mitochondrial ion homeostasis. Here we report a role of LETM1 in the organization of cristae structures. We identified four amino acid residues of human LETM1 that are crucial for complementation of the growth deficiency caused by gene deletion of a yeast LETM1 orthologue. Substituting amino acid residues with alanine disrupts the correct assembly of a protein complex containing LETM1 and prevents changes in the mitochondrial morphology induced by exogenous LETM1 expression. Moreover, the LETM1 protein changes the shapes of the membranes of in vitro-reconstituted proteoliposomes, leading to the formation of invaginated membrane structures on artificial liposomes. LETM1 mutant proteins with alanine substitutions fail to facilitate the formation of invaginated membrane structures, suggesting that LETM1 plays a fundamental role in the organization of mitochondrial membrane morphology.

Original languageEnglish
Article number99
JournalCommunications Biology
Volume3
Issue number1
DOIs
Publication statusPublished - Dec 1 2020

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ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • Medicine (miscellaneous)

Cite this

Nakamura, S., Matsui, A., Akabane, S., Tamura, Y., Hatano, A., Miyano, Y., Omote, H., Kajikawa, M., Maenaka, K., Moriyama, Y., Endo, T., & Oka, T. (2020). The mitochondrial inner membrane protein LETM1 modulates cristae organization through its LETM domain. Communications Biology, 3(1), [99]. https://doi.org/10.1038/s42003-020-0832-5