title: GpMyoF, a WD40 repeat-containing myosin associated with the myonemes of Gregarina polymorpha.
abstract: This study presents the first characterization of a WD40 repeat-containing myosin identified in the apicomplexan parasite Gregarina polymorpha. This 222.7 kDa myosin, GpMyoF, contains a canonical myosin motor domain, a neck domain with 6 IQ motifs, a tail domain containing short regions of predicted coiled-coil structure, and, most notably, multiple WD40 repeats at the C-terminus. In other proteins such repeats assemble into a beta-propeller structure implicated in mediating protein-protein interactions. Confocal microscopy suggests that GpMyoF is localized to the annular myonemes that gird the parasite cortex. Extraction studies indicate that this myosin shows an unusually tight association with the cytoskeletal fraction and can be solubilized only by treatment with high pH (11.5) or the anionic detergent sarkosyl. This novel myosin and its homologs, which have been identified in several related genera, appear to be unique to the Apicomplexa and represent the only myosins known to contain the WD40 domain. The function of this myosin in G. polymorpha or any of the other apicomplexan parasites remains uncertain.
authors: Department of Biology, Program in Cell Biology and Biochemistry, Bucknell University, Lewisburg, Pennsylvania 17837, USA. mheintze@bucknell.edu
authors: Matthew B
authors: MB
authors: Heintzelman
authors: Marcus J
authors: MJ
authors: Mateer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis / Q000276:immunology; D016782:Apicomplexa / Q000737:chemistry* / Q000145:classification / Q000235:genetics; D003001:Cloning, Molecular; D016384:Consensus Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D015151:Immunoblotting; D008840:Microfilament Proteins / Q000737:chemistry; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009218:Myosins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D010802:Phylogeny; D012333:RNA, Messenger / Q000737:chemistry; D016053:RNA, Protozoan / Q000235:genetics; D013712:Tenebrio / Q000469:parasitology
chemical_list: D000913:Antibodies, Protozoan; D008840:Microfilament Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; D009218:Myosins