A Look into the Heart of Cellular Waste Disposal
Published:31 May2023 Source:Max-Planck-Gesellschaft
To prevent our body's cells from overflowing with garbage and to keep them healthy, the waste inside them is constantly being disposed of. This cleaning process is called autophagy. Autophagy is a highly complex process involving many different proteins and protein complexes. We know many of them, but there are still fundamental gaps in our knowledge.
The research group at the Max Planck Institute for Multidisciplinary Sciences in Göttingen has now succeeded, for the first time, in producing all the proteins involved in the autophagy process in the laboratory and observing them directly as the autophagosomes assemble. In the first step, the scientists produced each individual protein component in the laboratory. In the next step, the team brought the individual protein complexes together. The complexes self-assembled into a protein supercomplex, the autophagy initiation complex.
To make autophagosomes, the autophagy initiation complex first creates a junction between a particular structure of the cell, the endoplasmic reticulum, and the autophagosome that forms. But researchers did not find a molecular "on" and "off" switch as in other molecular machines. Instead, the switch uses a highly unusual behavior of proteins: metamorphosis. This protein metamorphosis also gives the go-ahead for the assembly of the autophagy initiation complex at the right time and in the right place. Without metamorphosis, the initiation machine does not assemble.