title: C-terminal fragment of amebin promotes actin filament bundling, inhibits acto-myosin ATPase activity and is essential for amoeba migration.
abstract: Amebin [formerly termed as ApABP-FI; Sobczak et al. (2007) Biochem. Cell Biol. 85] is encoded in Amoeba proteus by two transcripts, 2672-nt and 1125-nt. A product of the shorter transcript (termed as C-amebin), comprising C-terminal 375 amino-acid-residue fragment of amebin, has been expressed and purified as the recombinant GST-fusion protein. GST-C-amebin bound both to monomeric and filamentous actin. The binding was Ca(2+)-independent and promoted filament bundling, as revealed with the transmission electron microscopy. GST-C-amebin significantly decreased MgATPase activity of rabbit skeletal muscle acto-S1. Removal with endoproteinase ArgC of a positively charged C-terminal region of GST-amebin containing KLASMWEQ sequence abolished actin-binding and bundling as well as the ATPase-inhibitory effect of C-amebin, indicating that this protein region was involved in the interaction with actin. Microinjection of amoebae with antibody against C-terminus of amebin significantly affected amoebae morphology, disturbed cell polarization and transport of cytoplasmic granules as well as blocked migration. These data indicate that amebin may be one of key regulators of the actin-cytoskeleton dynamics and actin-dependent motility in A. proteus.
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: Jolanta
authors.initials: J
authors.lastname: Jóźwiak
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Rzhepetskyy
authors.forename: Magdalena
authors.initials: M
authors.lastname: Sobczak
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Kocik
authors.forename: Radosław
authors.initials: R
authors.lastname: Skórzewski
authors.forename: Wanda
authors.initials: W
authors.lastname: Kłopocka
authors.forename: Maria Jolanta
authors.initials: MJ
authors.lastname: Rędowicz
mesh_terms: D008841:Actin Cytoskeleton / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D000595:Amino Acid Sequence; D000656:Amoeba / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D000818:Animals; D066298:In Vitro Techniques; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009068:Movement / Q000502:physiology; D046912:Multiprotein Complexes; D009218:Myosins / Q000037:antagonists & inhibitors*; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure; D011485:Protein Binding; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D046912:Multiprotein Complexes; D010446:Peptide Fragments; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; D009218:Myosins