title: Antagonistic Behaviors of NMY-1 and NMY-2 Maintain Ring Channels in the C. elegans Gonad.
abstract: Contractile rings play critical roles in a number of biological processes, including oogenesis, wound healing, and cytokinesis. In many cases, the activity of motor proteins such as nonmuscle myosins is required for appropriate constriction of these contractile rings. In the gonad of the nematode worm Caenorhabditis elegans, ring channels are a specialized form of contractile ring that are maintained at a constant diameter before oogenesis. We propose a model of ring channel maintenance that explicitly incorporates force generation by motor proteins that can act normally or tangentially to the ring channel opening. We find that both modes of force generation are needed to maintain the ring channels. We demonstrate experimentally that the type II myosins NMY-1 and NMY-2 antagonize each other in the ring channels by producing force in perpendicular directions: the experimental depletion of NMY-1/theoretical decrease in orthogonal force allows premature ring constriction and cellularization, whereas the experimental depletion of NMY-2/theoretical decrease in tangential force opens the ring channels and prevents cellularization. Together, our experimental and theoretical results show that both forces, mediated by NMY-1 and NMY-2, are crucial for maintaining the appropriate ring channel diameter and dynamics throughout the gonad.
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio.
authors.forename: Valerie C
authors.initials: VC
authors.lastname: Coffman
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta Canada.
authors.forename: Torah M
authors.initials: TM
authors.lastname: Kachur
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, Alberta Canada.
authors.forename: David B
authors.initials: DB
authors.lastname: Pilgrim
authors.affiliation: Department of Molecular Genetics, The Ohio State University, Columbus, Ohio; Department of Mathematics, The Ohio State University, Columbus, Ohio. Electronic address: dawes.33@osu.edu.
authors.forename: Adriana T
authors.initials: AT
authors.lastname: Dawes
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000254:growth & development* / Q000378:metabolism* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D006066:Gonads / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D008954:Models, Biological; D009119:Muscle Contraction; D024462:Myosin Type II / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D029742:Caenorhabditis elegans Proteins; D024462:Myosin Type II