title: AFM force measurements on microtubule-associated proteins: the projection domain exerts a long-range repulsive force.
abstract: Microtubule-associated proteins (MAPs) are thought to control spacing between microtubules. We propose that the projection domain is largely unstructured and exerts a long-range repulsive force that is predominantly entropic in origin, providing a physical mechanism for maintaining spacing. To test this hypothesis, we developed an experimental system where MAPs are electrostatically end-attached to a flat surface, such that the projection domains extend away from the surface. Atomic force microscopy force measurements on this system show that projection domains exert a long-range (>100 nm) repulsive force. This force depends on the ionic strength of the solution in a way that is consistent with a polyelectrolyte polymer brush.
authors.affiliation: Department of Physiology, Johns Hopkins University, Baltimore, MD 21205, USA.
authors.forename: R
authors.initials: R
authors.lastname: Mukhopadhyay
authors.forename: J H
authors.initials: JH
authors.lastname: Hoh
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D019277:Entropy; D018625:Microscopy, Atomic Force; D008869:Microtubule-Associated Proteins / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D008869:Microtubule-Associated Proteins