Identification of a novel Ezrin-binding site in syndecan-2 cytoplasmic domain

• Published in: FEBS letters Vol. 547; no. 1; pp. 212 - 216
• Main Authors: Granés, Francesc, Berndt, Christine, Roy, Christian, Mangeat, Paul, Reina, Manuel, Vilaró, Senén
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 17-07-2003
• Subjects: Amino Acid Sequence; Binding Sites; Binding, Competitive; Cloning, Molecular; Cytoskeletal Proteins; ERM, Ezrin/Radixin/Moesin; Ezrin/Radixin/Moesin proteins; GST, glutathione S-transferase; Humans; ICAM, intercellular adhesion molecule; Kinetics; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - metabolism; Molecular Sequence Data; NHE3, Na+/H+ exchanger 3; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Phosphoproteins - chemistry; Phosphoproteins - metabolism; Protein interaction; Proteoglycans - chemistry; Proteoglycans - metabolism; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Syndecan; Syndecan-2; ERM, Ezrin/Radixin/Moesin; GST, glutathione S-transferase; Ezrin/Radixin/Moesin proteins; ICAM, intercellular adhesion molecule; NHE3, Na +/H + exchanger 3; Protein interaction; Syndecan
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(03)00712-9

ERM (Ezrin/Radixin/Moesin) proteins are crosslinkers between plasma membrane proteins and the actin cytoskeleton, thereby involved in the formation of cell adhesion sites. Earlier work showed that Ezrin links syndecan-2 to the actin cytoskeleton. Here we provide evidence that the Ezrin N-terminal domain binds to the syndecan-2 cytoplasmic domain with an estimated
K
D of 0.71 μM and without the requirement of other proteins. We also studied the regions in the syndecan-2 cytoplasmic domain implicated in the binding to Ezrin. By truncating the syndecan-2 cytoplasmic domain and by oligopeptide competition assays we show that the Ezrin-binding sequence is not located in the positively charged juxtamembrane region (RMRKK), but in the neighboring sequence DEGSYD. We therefore conclude that the consensus sequence for Ezrin binding is unique among membrane proteins, suggesting a distinct regulation.