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Sisyphus, the Drosophila myosin XV homolog, traffics within filopodia transporting key sensory and adhesion cargos

TitleSisyphus, the Drosophila myosin XV homolog, traffics within filopodia transporting key sensory and adhesion cargos
Publication TypeJournal Article
Year of Publication2008
AuthorsLiu R, Woolner S, Johndrow JE, Metzger D, Flores A, Parkhurst SM
Date Published2008
ISBN Number0950-1991 (Print)0950-1991 (Linking)
KeywordsAmino Acid Sequence, Animals, Protein Binding, Cadherins/metabolism, Cell Adhesion, Drosophila melanogaster/*cytology/embryology/genetics/*metabolism, Drosophila Proteins/chemistry/deficiency/genetics/*metabolism, Embryo, Nonmammalian/cytology/embryology/metabolism, Gene Expression Regulation, Developmental, Humans, Molecular Sequence Data, Mutation/genetics, Myosins/chemistry/deficiency/genetics/*metabolism, Neurons, Afferent/cytology/metabolism, Reproductive Isolation, Protein Transport, Pseudopodia/*metabolism, Sequence Alignment

Unconventional myosin proteins of the MyTH-FERM superclass are involved in intrafilopodial trafficking, are thought to be mediators of membrane-cytoskeleton interactions, and are linked to several forms of deafness in mammals. Here we show that the Drosophila myosin XV homolog, Sisyphus, is expressed at high levels in leading edge cells and their cellular protrusions during the morphogenetic process of dorsal closure. Sisyphus is required for the correct alignment of cells on opposing sides of the fusing epithelial sheets, as well as for adhesion of the cells during the final zippering/fusion phase. We have identified several putative Sisyphus cargos, including DE-cadherin (also known as Shotgun) and the microtubule-linked proteins Katanin-60, EB1, Milton and aPKC. These cargos bind to the Sisyphus FERM domain, and their binding is in some cases mutually exclusive. Our data suggest a mechanism for Sisyphus in which it maintains a balance between actin and microtubule cytoskeleton components, thereby contributing to cytoskeletal cross-talk necessary for regulating filopodial dynamics during dorsal closure.