AVS 46th International Symposium
    Biomaterial Interfaces Group Wednesday Sessions
       Session BI-WeA

Paper BI-WeA3
Pulling Protein Networks in 2D

Wednesday, October 27, 1999, 2:40 pm, Room 613/614

Session: Biology at the Nanoscale
Presenter: G. Baneyx, University of Washington
Authors: G. Baneyx, University of Washington
V. Vogel, University of Washington
Correspondent: Click to Email
Fibronectin (Fn), an adhesion protein with multiple recognition sites, mediates cell attachment to synthetic and biological surfaces. In solution, Fn exists in a globular state where most of its recognition sites are buried in the protein core. Surface adsorption induces conformational changes in the protein that expose many of these sites. Furthermore, Fn assembles into detergent insoluble fibers on the surface of cells, and these matrices are considered to be the main functional form of the protein. The cell-mediated assembly of Fn into fibrillar matrices is a complex, multistep process that is still incompletely understood. This is due to the chemical complexity of the extracellular matrix, as well as a lack of experimental control over the molecular interactions and dynamic events. We will discuss how Fn fibril assembly into extended two-dimensional networks can be induced by adsorbing Fn from a physiological buffer solution to a dipalmitoylphosphatidylcholine (DPPC) monolayer. A sequential model for the assembly pathway is proposed. Striking similarities are found between the properties of these Fn fibrils assembled underneath DPPC monolayers and those found on cellular surfaces, as well as between the respective sequential assembly pathways. Spontaneous Fn fibril assembly underneath DPPC monolayers can now serve as a well controlled model system to study how different parameters such as the deletion of key Fn sequences, as well as alteration of solution conditions and the presence of other proteins, affect the molecular assembly pathway.