title: Liprin-alpha1 promotes cell spreading on the extracellular matrix by affecting the distribution of activated integrins.
abstract: Integrin activation is needed to link the extracellular matrix with the actin cytoskeleton during cell motility. Protrusion requires coordination of actin dynamics with focal-adhesion turnover. We report that the adaptor protein liprin-alpha1 is stably associated with the cell membrane. Lipin-alpha1 shows a localization that is distinct from that of activated beta1 integrins at the edge of spreading cells. Depletion of liprin-alpha1 inhibits the spreading of COS7 cells on fibronectin by affecting lamellipodia formation, whereas its overexpression enhances spreading, and lamellipodia and focal-adhesion formation at the cell edge. Cooperation between liprin-alpha1 and talin is needed, because either talin or liprin depletion prevents spreading in the presence of the other protein. The effects of liprin on spreading, but not its effects in the reorganization of the cell edge, are dependent on its interaction with leukocyte common antigen-related tyrosine phosphatase receptors. Therefore, liprin is an essential regulator of cell motility that contributes to the effectiveness of cell-edge protrusion.
authors.affiliation: Cell Adhesion Unit, Department of Neuroscience, San Raffaele University and San Raffaele Scientific Institute, 20132 Milano, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Asperti
authors.forename: Veronica
authors.initials: V
authors.lastname: Astro
authors.forename: Antonio
authors.initials: A
authors.lastname: Totaro
authors.forename: Simona
authors.initials: S
authors.lastname: Paris
authors.forename: Ivan
authors.initials: I
authors.lastname: de Curtis
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D002645:Chickens; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism; D005109:Extracellular Matrix / Q000201:enzymology / Q000378:metabolism*; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding; D011554:Pseudopodia / Q000378:metabolism; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2 / Q000378:metabolism; D016608:Talin / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D016023:Integrins; C094398:PPFIA1 protein, human; D016608:Talin; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2