Monday, December 27, 2010
Double life of bacterial elongation factor EF-Tu
Protein biosyntheses is performed by the ribosome and is assisted by a large number of accessory molecules, with several of them belonging to the GTPase class. EF-Tu is a GTPase which is responsible for bringing the amynoacyl-tRNA to the ribosome, and it is one of the most abundant proteins in bacteria.
So abundant, in fact, that it is impossible to explain this abundance by EF-Tu's role in translation. And indeed, recent microscopy investigations has shown how EF-Tu works as a part of bacterial cytosceleton.
EF-Tu works together with another bacterial structural protein, actin-like protein MreB, which froms spirals underneath bacterial membrane. In this tandem EF-Tu leads the formation of more dynamic MreB filaments.
In eucaryotes eEF1A does the job of EF-Tu and delivers the tRNA. It is involved in interactions with the cytosceleton just as it its bacterial counterpart, but instead of MreB it interacts with the filamentous actin, causing it to form bundles.
Bunai F, Ando K, Ueno H, & Numata O (2006). Tetrahymena eukaryotic translation elongation factor 1A (eEF1A) bundles filamentous actin through dimer formation. Journal of biochemistry, 140 (3), 393-9 PMID: 16877446
Defeu Soufo HJ, Reimold C, Linne U, Knust T, Gescher J, & Graumann PL (2010). Bacterial translation elongation factor EF-Tu interacts and colocalizes with actin-like MreB protein. Proceedings of the National Academy of Sciences of the United States of America, 107 (7), 3163-8 PMID: 20133608
Vats P, & Rothfield L (2007). Duplication and segregation of the actin (MreB) cytoskeleton during the prokaryotic cell cycle. Proceedings of the National Academy of Sciences of the United States of America, 104 (45), 17795-800 PMID: 17978175