title: Cell adhesion molecule Echinoid associates with unconventional myosin VI/Jaguar motor to regulate cell morphology during dorsal closure in Drosophila.
abstract: Echinoid (Ed) is a homophilic immunoglobulin domain-containing cell adhesion molecule (CAM) that localizes to adherens junctions (AJs) and cooperates with Drosophila melanogaster epithelial (DE)-cadherin to mediate cell adhesion. Here we show that Ed takes part in many processes of dorsal closure, a morphogenetic movement driven by coordinated cell shape changes and migration of epidermal cells to cover the underlying amnioserosa. Ed is differentially expressed, appearing in epidermis but not in amnioserosa cells. Ed functions independently from the JNK signaling pathway and is required to regulate cell morphology, and for assembly of actomyosin cable, filopodial protrusion and coordinated cell migration in dorsal-most epidermal cells. The effect of Ed on cell morphology requires the presence of the intracellular domain (Ed(intra)). Interestingly, Ed forms homodimers in vivo and Ed(intra) monomer directly associates with unconventional myosin VI/Jaguar (Jar) motor protein. We further show that ed genetically interacts with jar to control cell morphology. It has previously been shown that myosin VI is monomeric in vitro and that its dimeric form can associate with and travel processively along actin filaments. Thus, we propose that Ed mediates the dimerization of myosin VI/Jar in vivo which in turn regulates the reorganization and/or contraction of actin filaments to control changes in cell shape. Consistent with this, we found that ectopic ed expression in the amnioserosa induces myosin VI/Jar-dependent apical constriction of this tissue.
authors.affiliation: Institute of Molecular Medicine, Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30034, Republic of China.
authors.forename: Hui-Ping
authors.initials: HP
authors.lastname: Lin
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Chen
authors.forename: Shu-Yi
authors.initials: SY
authors.lastname: Wei
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Chen
authors.forename: Li-Hsun
authors.initials: LH
authors.lastname: Chang
authors.forename: Yuh-Ju
authors.initials: YJ
authors.lastname: Sun
authors.forename: San-Yuan
authors.initials: SY
authors.lastname: Huang
authors.forename: Jui-Chou
authors.initials: JC
authors.lastname: Hsu
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D048430:Cell Shape; D019281:Dimerization; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology* / Q000196:embryology* / Q000378:metabolism; D005260:Female; D048031:JNK Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008297:Male; D020409:Molecular Motor Proteins / Q000235:genetics / Q000378:metabolism; D009024:Morphogenesis; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D015815:Cell Adhesion Molecules; D029721:Drosophila Proteins; C422623:ED protein, Drosophila; D020409:Molecular Motor Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C089785:myosin VI; D000205:Actomyosin; D048031:JNK Mitogen-Activated Protein Kinases; D018995:Myosin Heavy Chains