Incorporation of integrins into artificial planar lipid membranes: characterization by plasmon-enhanced fluorescence spectroscopy

• Published in: Analytical biochemistry Vol. 333; no. 2; pp. 216 - 224
• Main Authors: Sinner, Eva-Kathrin, Reuning, Ute, Kök, Fatma Nese, Saccà, Barbara, Moroder, Luis, Knoll, Wolfgang, Oesterhelt, Dieter
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.10.2004
• Subjects: Antibodies; Artificial membranes; Biofunctionalized surfaces; Collagen Type IV - metabolism; Gold; Integrin; Integrin alpha1beta1 - metabolism; Integrins - chemistry; Integrins - metabolism; Membrane proteins; Membranes, Artificial; Spectrometry, Fluorescence; Surface Plasmon Resonance; Surface plasmon-enhanced fluorescence spectroscopy; Biofunctionalized surfaces; Surface plasmon resonance; Integrin; Surface plasmon-enhanced fluorescence spectroscopy; Artificial membranes; Membrane proteins
• ISSN: 0003-2697; 1096-0309
• DOI: 10.1016/j.ab.2004.05.022

An optimized peptide-tethered artificial lipid membrane system has been developed. Integrins (cell adhesion receptors) were functionally incorporated into this membrane model and integrin–ligand interactions were analyzed by surface plasmon-enhanced fluorescence spectroscopy (SPFS). The transmembrane receptors α vβ 3 and α 1β 1 of the integrin superfamily were incorporated into a lipid-functionalized peptide layer by vesicle spreading. Consecutive layer formations were monitored by surface plasmon spectroscopy (SPS). Orientation and accessibility of the membrane receptor α vβ 3 was reliably assessed by specific and reproducible binding of selective antibodies. Moreover, full retention of the functional properties of this receptor was verified by specific and reversible binding of natural ligands. Functional integrity of incorporated integrins was maintained over a time period of 72 h. The integrin/extracellular matrix ligand complexes, whose formations are known to depend on the presence of divalent cations, were lost upon addition of ethylenediaminetetraacetate. Therefore, regeneration of the surface for further binding experiments with minimized unspecific ligand association was possible. These results demonstrate that integrins can be functionally incorporated into peptide-tethered artificial membranes. In combination with the SPS/SPFS method, this artificial membrane system provides a reliable experimental platform for investigation of isolated membrane proteins under experimental conditions resembling those of their native environment.