Go your own way: Membrane targeting sequences

Distributing proteins to the correct sub-cellular compartments and organelles is crucial for the proper functionality of the proteins as well as for the general function of eukaryotic cells. Cellular targeting is best understood in the case of endoplasmic reticulum (ER) proteins targeted co-translationally via the signal recognition particle (SRP)-mediated pathway but various targeting mechanisms, signals and pathways are in place depending on organism, organelle and protein types to allow for specificity and efficiency of protein targeting. This review aims to give an overview on membrane targeting sequences taking into account the connected targeting mechanism and co-factors. It focusses on primary targeting to membranes of the endoplasmic reticulum, chloroplast, mitochondrion, peroxisome, nucleus and tonoplast