Until now, little was known about the identity of proteins which are disposed via autophagy. In an unbiased approach to shed light on this conundrum, the Behrends group used a novel proteomics technology to selectively capture all cargo proteins carried by autophagosomes in living cells.

The outcome was a long list of 1,147 proteins – amongst them numerous involved in mitochondrial function, a rather unexpected result considering that no treatment triggering mitophagy was applied. The researchers followed up on this and made a yet more surprising discovery:

They found that proteins from several mitochondrial subcompartments are directed towards autophagosomes in a piecemeal fashion, meaning without degradation of the entire organelle. This establishes a novel mechanism of mitophagy, which may function to maintain the mitochondrial household under basal growth condition. The study was largely funded by the CRC 1177 (www.sfb1177.de) and carried out at IBC2 and at Ludwig-Maximilians-Universität (LMU) München, to where the Behrends lab recently moved. The results are published in today’s issue of Molecular Cell.

Image: Design by Käthe Schönle