title: In indirect flight muscles Drosophila projectin has a short PEVK domain, and its NH2-terminus is embedded at the Z-band.
abstract: Insect indirect flight muscles (IFM) contain a third filament system made up of elastic connecting or C-filaments. The giant protein projectin is the main, if not the only, component of these structures. In this study we found that projectin is oriented within the IFM sarcomere with its NH2-terminus embedded in the Z-bands. We demonstrate that this protein has an elastic region that can be detected by the movement of specific epitopes following stretch. One possible elastic region is the PEVK-like domain located close to the NH2-terminus. The amino acid length of this region is short, and 52% of its residues are P, E, V or K. We propose a model in which projectin extends from the Z-band to the lateral borders of the A-band. The PEVK-like domain and a series of Ig domains spanning the intervening I-band may provide the elastic properties of projectin.
authors.affiliation: Department of Biology, College of Charleston, Charleston, SC 29424, USA. southgatea@cofc.edu
authors.forename: Agnes
authors.initials: A
authors.lastname: Ayme-Southgate
authors.forename: Judith
authors.initials: J
authors.lastname: Saide
authors.forename: Richard
authors.initials: R
authors.lastname: Southgate
authors.forename: Christophe
authors.initials: C
authors.lastname: Bounaix
authors.forename: Anthony
authors.initials: A
authors.lastname: Cammarato
authors.forename: Sunita
authors.initials: S
authors.lastname: Patel
authors.forename: Catherine
authors.initials: C
authors.lastname: Wussler
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002154:Calpain / Q000494:pharmacology; D015870:Gene Expression / Q000235:genetics; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008958:Models, Molecular; D009124:Muscle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009210:Myofibrils / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D009218:Myosins / Q000378:metabolism; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D012518:Sarcomeres / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D009124:Muscle Proteins; D020033:Protein Isoforms; C078033:projectin; D002154:Calpain; D009218:Myosins