Localization of the membrane binding sites of Era in Escherichia coli.

Era is a GTP-binding protein that is essential for normal cell growth and division in Escherichia coli. In view of the fact that eukaryotic proteins similar to Era are membrane-associated and important in membrane signalling pathways, experiments were carried out to establish the intracellular location of Era. Immunoelectron microscopy was employed to demonstrate that Era resides at or very near the internal surface of the cytoplasmic membrane, which is a location expected for a membrane signalling protein. In addition, Era occurs in patches that may correspond to areas that are potential sites of septation.