A giant called MIMAS in the cell power plants

Mega protein complex with surprising properties discovered in mitochondria

12-Mar-2024

mitochondria provide the majority of the body's energy supply and are considered the power plants of the cells. The energy comes from cellular respiration, in which metabolic products are burned in the inner mitochondrial membrane. Mitochondria also play an important role in the metabolism of cells, both in the breakdown and synthesis of numerous cell building blocks. Many of these processes depend on proteins in the inner membrane, which has an extraordinarily high protein density. Defects in these proteins lead to serious diseases in humans. A team led by Dr. Heike Rampelt and Prof. Dr. Nikolaus Pfanner from the Institute of Biochemistry and Molecular Biology at the University of Freiburg has now discovered a new mega-protein complex with surprising properties in the inner mitochondrial membrane. Their findings have been published in the journal Cell Reports.

Like specialized assembly line workers

The new complex is called MIMAS(mitochondrial multifunctional assembly); it is named after a giant in Greek mythology because of its unusual size. It integrates numerous different processes into a common platform - thus deviating from the previous paradigm that the components of a protein complex typically perform a common function.

As the research team was able to show, MIMAS combines very different functions in contrast to the established mitochondrial protein complexes: it comprises numerous factors that assemble the respiratory chain complexes like specialized assembly line workers. In addition, there are diverse transport proteins that transport ions or metabolic products between mitochondria and the rest of the cell, as well as enzymes involved in energy metabolism and membrane lipid synthesis.

Astonishing functional diversity

This astonishing functional diversity in MIMAS is not the only special feature of the complex: its stability also depends on a specific membrane lipid whose synthesis enzyme is itself a MIMAS component. These observations suggest that MIMAS is the founder of a novel organizing principle in the inner mitochondrial membrane: proteins of different functions are organized in a megacomplex, which could be an important target for regulation, for example in metabolic changes or diseases.

Note: This article has been translated using a computer system without human intervention. LUMITOS offers these automatic translations to present a wider range of current news. Since this article has been translated with automatic translation, it is possible that it contains errors in vocabulary, syntax or grammar. The original article in German can be found here.

Original publication

Patrick Horten, Kuo Song, Joshua Garlich, Robert Hardt, Lilia Colina-Tenorio, Susanne E. Horvath, Uwe Schulte, Bernd Fakler, Martin van der Laan, Thomas Becker, Rosemary A. Stuart, Nikolaus Pfanner, Heike Rampelt; "Identification of MIMAS, a multifunctional mega-assembly integrating metabolic and respiratory biogenesis factors of mitochondria"; Cell Reports, Volume 43

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