title: The Plasmodium Class XIV Myosin, MyoB, Has a Distinct Subcellular Location in Invasive and Motile Stages of the Malaria Parasite and an Unusual Light Chain.
abstract: Myosin B (MyoB) is one of the two short class XIV myosins encoded in the Plasmodium genome. Class XIV myosins are characterized by a catalytic "head," a modified "neck," and the absence of a "tail" region. Myosin A (MyoA), the other class XIV myosin in Plasmodium, has been established as a component of the glideosome complex important in motility and cell invasion, but MyoB is not well characterized. We analyzed the properties of MyoB using three parasite species as follows: Plasmodium falciparum, Plasmodium berghei, and Plasmodium knowlesi. MyoB is expressed in all invasive stages (merozoites, ookinetes, and sporozoites) of the life cycle, and the protein is found in a discrete apical location in these polarized cells. In P. falciparum, MyoB is synthesized very late in schizogony/merogony, and its location in merozoites is distinct from, and anterior to, that of a range of known proteins present in the rhoptries, rhoptry neck or micronemes. Unlike MyoA, MyoB is not associated with glideosome complex proteins, including the MyoA light chain, myosin A tail domain-interacting protein (MTIP). A unique MyoB light chain (MLC-B) was identified that contains a calmodulin-like domain at the C terminus and an extended N-terminal region. MLC-B localizes to the same extreme apical pole in the cell as MyoB, and the two proteins form a complex. We propose that MLC-B is a MyoB-specific light chain, and for the short class XIV myosins that lack a tail region, the atypical myosin light chains may fulfill that role.
authors: From the Divisions of Parasitology.
authors: Noor A
authors: NA
authors: Yusuf
authors: From the Divisions of Parasitology.
authors: Judith L
authors: JL
authors: Green
authors: the School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG2 7UH, United Kingdom.
authors: Richard J
authors: RJ
authors: Wall
authors: From the Divisions of Parasitology.
authors: Ellen
authors: E
authors: Knuepfer
authors: From the Divisions of Parasitology.
authors: Robert W
authors: RW
authors: Moon
authors: From the Divisions of Parasitology.
authors: Christina
authors: C
authors: Schulte-Huxel
authors: the Institute of Cell Biology, University of Bern, CH-3012 Bern, Switzerland, and.
authors: Rebecca R
authors: RR
authors: Stanway
authors: Physical Biochemistry, and.
authors: Stephen R
authors: SR
authors: Martin
authors: Molecular Structure, MRC National Institute for Medical Research, London NW7 1AA, United Kingdom.
authors: Steven A
authors: SA
authors: Howell
authors: the Institute of Chemical Biology, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.
authors: Christopher H
authors: CH
authors: Douse
authors: the Institute of Chemical Biology, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.
authors: Ernesto
authors: E
authors: Cota
authors: the Institute of Chemical Biology, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.
authors: Edward W
authors: EW
authors: Tate
authors: the School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG2 7UH, United Kingdom.
authors: Rita
authors: R
authors: Tewari
authors: From the Divisions of Parasitology, aholder@nimr.mrc.ac.uk.
authors: Anthony A
authors: AA
authors: Holder
mesh_terms: D000595:Amino Acid Sequence; D002147:Calmodulin / Q000737:chemistry; D002942:Circular Dichroism; D019084:Fluorescent Antibody Technique, Indirect; D049452:Green Fluorescent Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D018994:Myosin Light Chains / Q000737:chemistry; D024507:Nonmuscle Myosin Type IIA / Q000737:chemistry; D024501:Nonmuscle Myosin Type IIB / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D010962:Plasmodium berghei / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000378:metabolism*; D016790:Plasmodium knowlesi / Q000378:metabolism*; D011485:Protein Binding; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D002147:Calmodulin; D018994:Myosin Light Chains; D010455:Peptides; D015800:Protozoan Proteins; D049452:Green Fluorescent Proteins; D024507:Nonmuscle Myosin Type IIA; D024501:Nonmuscle Myosin Type IIB
keywords: Invasion; Malaria; Molecular Motor; Myosin; Myosin Light Chain; Parasite; Peptide Interaction; Plasmodium