Mitochondria- ER tethering

Mitochondria are important organelle that produce ATP in cells. Even if a lot of information are available about the function and evolutionary biology related to this cellular district, few is understood about the communication between mitochondria and the rest of cells in terms of molecular transport. In particular, some proteins have been recognized to form junctions between mitochondria and endoplasmic reticulum (ER) that is the compartment responsible of lipids synthesis and export into vesicles, but still be mysterious the nature of the connection.

Science published an important paper about this topic: authors identified a method to genetically screen and recognize proteins involved in the connection between mitochondria and ER in yeast. They designed a synthetic mitochondria- ER tether, called ChiMERA, consisting of an N-terminal mitochondrial signal sequence and a transmembrane domain from protein Tom70, connected through the central GFP domain to C-terminal ER tail anchor from protein Ubc6. The expression of ChiMERA in yeast strain that showed lethal mutations in mdm12 gene, important for mitochondria morphology and functionality, rescued the growth suggesting that the correct interaction between mitochondria and ER was achieved. In summary, this work acquires a pivotal role in research of other native organelle tethers and, maybe in far future to replace this cellular function with artificial proteins, if needed.