Regulatory role of signal sequence modification in mitochondrial biogenesis and protein quality control

Dr. Thomas Becker and Prof. Dr. Chris Meisinger (Institute for Biochemistry and Molecular Biology, ZBMZ, and BIOSS Centre for Biological Signalling Studies, University of Freiburg)

The majority of mitochondrial proteins are synthesized on cytosolic ribosomes with an N-terminal signal information, termed presequence. These preproteins are imported via the translocase of the outer membrane (TOM complex) and the presequence translocase (TIM23 complex) into the mitochondrial matrix or the inner membrane. Proteases in the matrix including the mitochondrial processing peptidase remove the signal peptide to allow proper folding of the imported protein. This project will address regulatory mechanisms of the import process. Phosphorylation of translocase subunits and a complicated network of processing peptidases reveal that the translocation is highly regulated to adapt to cellular needs.