Researchers discover a new basic principle of the mitochondria architecture

September 14, 2012
The protein complex MINOS plays a key role in the formation of the two membrane systems of mitochondria. MINOS is necessary for the architecture of the inner membrane and helps TOM and SAM embed proteins in the outer membrane by forming membrane bridges. Credit: Ralf Zerbes

A team of scientists at the University of Freiburg led by Dr. Martin van der Laan has achieved groundbreaking new insights into the structure of mitochondria. Mitochondria are the microscopic power plants of the cell that harness the energy stored in food, thus enabling central life functions. This conversion of energy takes place in delicately formed cavities of the biological membranes inside mitochondria. Defects in these fine membrane structures can lead to severe diseases of the muscles and the central nervous system. A sophisticated molecular machine of the inner membrane that the Freiburg team already discovered in 2011 is not only responsible for forming the characteristic structures within mitochondria but evidently also plays an important role in assembling the outer membrane enclosing these organelles, as the scientists now report in the renowned journal Molecular Biology of the Cell.

The protein machine studied by the scientists is essential for maintaining the typical architecture inside the and have thus received the name "Mitochondrial Organizing System" (MINOS). In their latest study, the Freiburg researchers and their colleagues in Graz, Austria, Warsaw, Poland, and Groningen, Netherlands, demonstrate that the role of MINOS in creating the mitochondrial architecture is clearly more extensive than previously assumed. In a joint research effort between the Collaborative Research Center 746 and the Cluster of Excellence Centre for Biological Signalling Studies (BIOSS), Dr. Maria Bohnert, Lena-Sophie Wenz and Ralf Zerbes found out how MINOS connects the distinct membrane systems of the mitochondria with each other.

The membrane complexes SAM and TOM play a key role in this process. They use tunnel-shaped structures to transport proteins into the mitochondrion and then embed them in the outer membrane. In their latest study, the Freiburg scientists demonstrate that the MINOS component Fcj1 of the Mitofilin participates directly in this process, which is essential for the survival of the cells. The inactivation of Fcj1 inhibits the integration of proteins into the mitochondrial outer membrane. These findings show how molecular switches affecting the connectivity of mitochondrial membranes control the assembly and function of the cellular power plants. These newly gained insights improve our understanding of the basic principles of the architecture of mitochondria. In the future they could help scientists to understand and influence mechanisms of diseases that involve changes in the fine structure of mitochondria.

Explore further: How mitochondria get their membranes bent

More information: Bohnert M, Wenz LS, Zerbes RM, Horvath SE, Stroud DA, von der Malsburg K, Müller JM, Oeljeklaus S, Perschil I, Warscheid B, Chacinska A, Veenhuis M, van der Klei IJ, Daum G, Wiedemann N, Becker T, Pfanner N, van der Laan M: "Role of MINOS in protein biogenesis of the mitochondrial outer membrane", in: Molecular Biology of the Cell, published online August 23, 2012.

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1.3 / 5 (14) Sep 14, 2012
Notice how the researchers do not mention anything about evolution in this story. The reason is quite clear and simple: firstly it contributes absolutely nothing to the research and secondly it should be absolutely clear that the irreducible complexity involved rules out any random, step by step development. ESPECIALLY since life wouldn't even begin to exist without the mitochondria.
3 / 5 (8) Sep 14, 2012
shut the fuck up kevin, we are tired of your strawmans. go read your bible or pray to your god for us lowly heathens if you love and believe in it so desperately.
5 / 5 (2) Sep 14, 2012
life wouldn't even begin to exist without the mitochondria
Life probably evolved in anaerobic environment, so that mitochondria evolved later, when photosynthetic bacteria increased the concentration of oxygen in the atmosphere. According to Lynn Margulius the composition of mitochondrial membranes provides a clue of their endosymbiotic origin: they're cells of former green bacteria, which lost their photosynthetic dyes and which were used with reversed function of their ATP pumps.
5 / 5 (4) Sep 14, 2012
Creationists shouldn't comment on science, it is hilarious to see.

Bacteria and Archaea has no mitochondrion endosymbionts, which themselves are of bacterial origin.

The reason evolution isn't much mentioned is because it is a functional study. But it describe evolution in the abstract: "Mitochondria lacking mitofilin, the large core subunit of MINOS, are impaired in the biogenesis of β-barrel proteins of the outer membrane, whereas mutant mitochondria lacking any of the other five MINOS subunits import β-barrel proteins like wild-type mitochondria." So they used evolutionary mechanisms to study the biological system.

A result that crushes remaining hopes of creationists was presented yesterday. It turns out Viruses is a 4th domain of life and is the missing piece that unifies and roots the tree. See especially fig 3, that shows the new ToL. [ http://www.biomed...-156.pdf ] Now all biological systems are rooted in an evolutionary LUCA!
5 / 5 (3) Sep 15, 2012
Errr. Kevin my little Tard.

The cells comprising most life on earth have no mitochondria.

Did you fail grade 9 Biology?

"ESPECIALLY since life wouldn't even begin to exist without the mitochondria." - KevinTard

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