Identification of a novel Ezrin-binding site in syndecan-2 cytoplasmic domain.
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 microM 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.
Granés
Francesc
F
Department of Cellular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain.
Berndt
Christine
C
Roy
Christian
C
Mangeat
Paul
P
Reina
Manuel
M
Vilaró
Senén
S
D000595:Amino Acid Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins; D006801:Humans; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism*; D011509:Proteoglycans / Q000737:chemistry* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D053669:Syndecan-2; D000099149:Ezrin
D003598:Cytoskeletal Proteins; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D011509:Proteoglycans; D011993:Recombinant Fusion Proteins; D053669:Syndecan-2; D000099149:Ezrin; C508245:SDC2 protein, human