title: Enlazin, a natural fusion of two classes of canonical cytoskeletal proteins, contributes to cytokinesis dynamics.
abstract: Cytokinesis requires a complex network of equatorial and global proteins to regulate cell shape changes. Here, using interaction genetics, we report the first characterization of a novel protein, enlazin. Enlazin is a natural fusion of two canonical classes of actin-associated proteins, the ezrin-radixin-moesin family and fimbrin, and it is localized to actin-rich structures. A fragment of enlazin, enl-tr, was isolated as a genetic suppressor of the cytokinesis defect of cortexillin-I mutants. Expression of enl-tr disrupts expression of endogenous enlazin, indicating that enl-tr functions as a dominant-negative lesion. Enlazin is distributed globally during cytokinesis and is required for cortical tension and cell adhesion. Consistent with a role in cell mechanics, inhibition of enlazin in a cortexillin-I background restores cytokinesis furrowing dynamics and suppresses the growth-in-suspension defect. However, as expected for a role in cell adhesion, inhibiting enlazin in a myosin-II background induces a synthetic cytokinesis phenotype, frequently arresting furrow ingression at the dumbbell shape and/or causing recession of the furrow. Thus, enlazin has roles in cell mechanics and adhesion, and these roles seem to be differentially significant for cytokinesis, depending on the genetic background.
authors.affiliation: Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Edelyn
authors.initials: E
authors.lastname: Octtaviani
authors.forename: Janet C
authors.initials: JC
authors.lastname: Effler
authors.forename: Douglas N
authors.initials: DN
authors.lastname: Robinson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001696:Biomechanical Phenomena; D002448:Cell Adhesion; D048708:Cell Growth Processes; D048749:Cytokinesis; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004023:Dictyostelium / Q000166:cytology* / Q000378:metabolism*; D020868:Gene Silencing; D008840:Microfilament Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010446:Peptide Fragments / Q000378:metabolism; D010641:Phenotype; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; D008840:Microfilament Proteins; D010446:Peptide Fragments; D015800:Protozoan Proteins; C101109:ctxA protein, Dictyostelium discoideum