title: Formation of irreversibly bound annexin A1 protein domains on POPC/POPS solid supported membranes.
abstract: The specific interaction of annexin A1 with phospholipid bilayers is scrutinized by means of scanning force and fluorescence microscopy, quartz crystal microbalance, ellipsometry, and modeled by dynamic Monte Carlo simulations. It was found that POPC/POPS bilayers exhibit phase separation in POPC- and POPS-enriched domains as a function of Ca2+ concentration. Annexin A1 interacts with POPC/POPS bilayers by forming irreversibly bound protein domains with monolayer thickness on POPS-enriched nanodomains, while the attachment of proteins to the POPC-enriched regions is fully reversible. A thorough kinetic analysis of the process reveals that both, the binding constant of annexin A1 at the POPC-rich areas as well as the irreversible adsorption rate to the POPS-rich domains increases with calcium ion concentration. Based on the thermodynamic and kinetic data, a possible mechanism of the annexin A1 membrane interaction can be proposed.
authors.affiliation: Institute of Physical Chemistry, University of Mainz, Welder-Weg 11, Mainz, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Faiss
authors.forename: Katja
authors.initials: K
authors.lastname: Kastl
authors.forename: Andreas
authors.initials: A
authors.lastname: Janshoff
authors.forename: Claudia
authors.initials: C
authors.lastname: Steinem
mesh_terms: D000327:Adsorption; D000818:Animals; D017305:Annexin A1 / Q000737:chemistry* / Q000378:metabolism*; D055592:Biophysical Phenomena; D001703:Biophysics; D002118:Calcium / Q000378:metabolism; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D009010:Monte Carlo Method; D010713:Phosphatidylcholines / Q000737:chemistry / Q000378:metabolism; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance
chemical_list: D017305:Annexin A1; D008051:Lipid Bilayers; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010718:Phosphatidylserines; C050294:1-palmitoyl-2-oleoylglycero-3-phosphoserine; D002118:Calcium; C028694:1-palmitoyl-2-oleoylphosphatidylcholine