title: Hydrodynamic flow-mediated protein sorting on the cell surface of trypanosomes.
abstract: The unicellular parasite Trypanosoma brucei rapidly removes host-derived immunoglobulin (Ig) from its cell surface, which is dominated by a single type of glycosylphosphatidylinositol-anchored variant surface glycoprotein (VSG). We have determined the mechanism of antibody clearance and found that Ig-VSG immune complexes are passively sorted to the posterior cell pole, where they are endocytosed. The backward movement of immune complexes requires forward cellular motility but is independent of endocytosis and of actin function. We suggest that the hydrodynamic flow acting on swimming trypanosomes causes directional movement of Ig-VSG immune complexes in the plane of the plasma membrane, that is, immunoglobulins attached to VSG function as molecular sails. Protein sorting by hydrodynamic forces helps to protect trypanosomes against complement-mediated immune destruction in culture and possibly in infected mammals but likewise may be of functional significance at the surface of other cell types such as epithelial cells lining blood vessels.
authors.affiliation: Institut für Mikrobiologie und Genetik, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287, Darmstadt, Germany. engstler@bio.tu-darmstadt.de
authors.forename: Markus
authors.initials: M
authors.lastname: Engstler
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfohl
authors.forename: Stephan
authors.initials: S
authors.lastname: Herminghaus
authors.forename: Michael
authors.initials: M
authors.lastname: Boshart
authors.forename: Geert
authors.initials: G
authors.lastname: Wiegertjes
authors.forename: Niko
authors.initials: N
authors.lastname: Heddergott
authors.forename: Peter
authors.initials: P
authors.lastname: Overath
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology / Q000302:isolation & purification; D001696:Biomechanical Phenomena; D002465:Cell Movement; D003165:Complement System Proteins; D003599:Cytoskeleton / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D004705:Endocytosis; D006801:Humans; D007700:Kinetics; D008018:Life Cycle Stages; D008024:Ligands; D008970:Molecular Weight; D021381:Protein Transport; D013552:Swine; D013696:Temperature; D014346:Trypanosoma brucei brucei / Q000166:cytology* / Q000254:growth & development / Q000276:immunology / Q000378:metabolism*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000378:metabolism*
chemical_list: D000199:Actins; D000913:Antibodies, Protozoan; D008024:Ligands; D014643:Variant Surface Glycoproteins, Trypanosoma; D003165:Complement System Proteins