title: Nanomechanical properties of composite protein networks of erythroid membranes at lipid surfaces.
abstract: Erythrocyte membranes have been particularly useful as a model for studies of membrane structure and mechanics. Native erythroid membranes can be electroformed as giant unilamellar vesicles (eGUVs). In the presence of ATP, the erythroid membrane proteins of eGUVs rearrange into protein networks at the microscale. Here, we present a detailed nanomechanical study of individual protein microfilaments forming the protein networks of eGUVs when spread on supporting surfaces. Using Peak Force tapping Atomic Force Microscopy (PF-AFM) in liquid environment we have obtained the mechanical maps of the composite lipid-protein networks supported on solid surface. In the absence of ATP, the protein pool was characterized by a Young's Modulus Epool≈5-15MPa whereas the complex filaments were found softer after protein supramolecular rearrangement; Efil≈0.4MPa. The observed protein softening and reassembling could be relevant for understanding the mechanisms of cytoskeleton reorganization found in pathological erythrocytes or erythrocytes that are affected by biological agents.
authors.affiliation: Instituto de Microelectrónica de Madrid, CSIC, 28760 Tres Cantos, Spain.
authors.forename: Mario
authors.initials: M
authors.lastname: Encinar
authors.affiliation: IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Casado
authors.affiliation: Instituto de Microelectrónica de Madrid, CSIC, 28760 Tres Cantos, Spain.
authors.forename: Alicia
authors.initials: A
authors.lastname: Calzado-Martín
authors.affiliation: Dpt. Physical Chemistry I, Universidad Complutense de Madrid, 28040 Madrid, Spain; Instituto de Investigación Hospital Doce de Octubre (i+12), 28041 Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Natale
authors.affiliation: Instituto de Microelectrónica de Madrid, CSIC, 28760 Tres Cantos, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: San Paulo
authors.affiliation: Instituto de Microelectrónica de Madrid, CSIC, 28760 Tres Cantos, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Calleja
authors.affiliation: IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain; Instituto de Catálisis y Petroleoquímica, CSIC, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain.
authors.forename: Marisela
authors.initials: M
authors.lastname: Vélez
authors.affiliation: Dpt. Physical Chemistry I, Universidad Complutense de Madrid, 28040 Madrid, Spain; Instituto de Investigación Hospital Doce de Octubre (i+12), 28041 Madrid, Spain. Electronic address: monroy@quim.ucm.es.
authors.forename: Francisco
authors.initials: F
authors.lastname: Monroy
authors.affiliation: Dpt. Physical Chemistry I, Universidad Complutense de Madrid, 28040 Madrid, Spain; Instituto de Investigación Hospital Doce de Octubre (i+12), 28041 Madrid, Spain. Electronic address: ivanlopez@quim.ucm.es.
authors.forename: Iván
authors.initials: I
authors.lastname: López-Montero
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D001696:Biomechanical Phenomena; D003599:Cytoskeleton / Q000737:chemistry* / Q000648:ultrastructure; D055119:Elastic Modulus; D004910:Erythrocyte Membrane / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D013050:Spectrometry, Fluorescence; D053835:Unilamellar Liposomes / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D008565:Membrane Proteins; D053835:Unilamellar Liposomes; D000255:Adenosine Triphosphate
keywords: AFM; Cytoskeleton reconstitution; Erythrocyte; Giant vesicles; Lipid membrane; PeakForce tapping quantitative nanomechanical mapping