title: Identification of the membrane receptor of a class XIV myosin in Toxoplasma gondii.
abstract: Apicomplexan parasites exhibit a unique form of substrate-dependent motility, gliding motility, which is essential during their invasion of host cells and during their spread between host cells. This process is dependent on actin filaments and myosin that are both located between the plasma membrane and two underlying membranes of the inner membrane complex. We have identified a protein complex in the apicomplexan parasite Toxoplasma gondii that contains the class XIV myosin required for gliding motility, TgMyoA, its associated light chain, TgMLC1, and two novel proteins, TgGAP45 and TgGAP50. We have localized this complex to the inner membrane complex of Toxoplasma, where it is anchored in the membrane by TgGAP50, an integral membrane glycoprotein. Assembly of the protein complex is spatially controlled and occurs in two stages. These results provide the first molecular description of an integral membrane protein as a specific receptor for a myosin motor, and further our understanding of the motile apparatus underlying gliding motility in apicomplexan parasites.
authors.affiliation: Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, 108 Taylor Hall, CB# 7090, Chapel Hill, NC 27599, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Gaskins
authors.forename: Stacey
authors.initials: S
authors.lastname: Gilk
authors.forename: Nicolette
authors.initials: N
authors.lastname: DeVore
authors.forename: Tara
authors.initials: T
authors.lastname: Mann
authors.forename: Gary
authors.initials: G
authors.lastname: Ward
authors.forename: Con
authors.initials: C
authors.lastname: Beckers
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002465:Cell Movement / Q000235:genetics; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D020409:Molecular Motor Proteins; D008969:Molecular Sequence Data; D018994:Myosin Light Chains / Q000378:metabolism; D009218:Myosins / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014122:Toxoplasma / Q000166:cytology / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D020409:Molecular Motor Proteins; D018994:Myosin Light Chains; D020033:Protein Isoforms; D015800:Protozoan Proteins; D011956:Receptors, Cell Surface; D009218:Myosins