Ezrin, radixin and moesin (ERM) proteins are now more and more recognized to play a key role in a large number of important physiological processes such as morphogenesis, cancer metastasis and virus infection. Several recent reviews extensively discuss their biological functions [1][2][3][4]. In this review, we will first remind the main features of this family of proteins, which are now known as linkers and regulators of the plasma membrane/cytoskeleton linkage. We will then briefly review their implication in pathological processes such as cancer and viral infection. In a second part, we will focus on biochemical and biophysical approaches to study ERM interaction with lipid membranes and conformational change in well-defined environments. In vitro studies using biomimetic lipid membranes, especially large unilamellar vesicles (LUVs), giant unilamellar vesicles (GUVs) and supported lipid bilayers (SLBs) and recombinant proteins help to understand the molecular mechanism of conformational activation of ERM proteins. These tools are aimed to decorticate the different steps of the interaction, to simplify the experiments performed in vivo in much more complex biological environments.
KeywordsEzrin; radixin and moesin; biomimetic membranes; phosphoinositol (4,5)-bisphosphate (PIP 2 ); large unilamellar vesicles; supported lipid bilayers; giant unilamelar vesicles Corresponding author: Catherine Picart, CNRS UMR 5628 (LMGP), Grenoble Institute of Technology and CNRS, 3 parvis Louis Néel, F-38016 Grenoble Cedex, France.
Europe PMC Funders GroupAuthor Manuscript Biochimie. Author manuscript; available in PMC 2014 July 28.
Published in final edited form as:Biochimie. 2013 January ; 95(1): 3-11. doi:10.1016/j.biochi.2012.09.033.
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Biological importance of Ezrin, Radixin and Moesin
General overview of ERM proteins (Ezrin, Radixin, Moesin)ERM proteins are localized at the plasma membrane in actin-rich surface structures (Fig 1) [5], such as microvilli, membrane ruffles, and lamellipodia in gut cells, lymphocytes, hepatocytes, spermatozoids, fibroblasts and in a variety of other cell types [5][6][7][8][9]. They are involved in various physiological processes including establishment of cell polarity, cell motility and cell signaling [10]. They act as linkers between the plasma membrane and the cortical actin cytoskeleton. From a structural point of view, ERMs are constituted of 3 domains : a membrane binding domain, also known as FERM (for band 4.1 protein, ezrin, radixin and moesin), and intermediary region and a actin binding domain called C-ERMAD (for C-terminal ERM-association domain) (Fig 2A).The FERM domain, constituted of ~300 amino acids, is characteristic of the proteins of the band 4.1 superfamily. These proteins also present other types of domains, including PDZ, tyrosine phosphatase, SH2-like, tyrosine kinase, kinase-like, myosin head, and PH domains [11]. In ERM proteins, the FERM domain is followed by a long α-helical region, whi...