title: Equarin is involved in cell adhesion by means of heparan sulfate proteoglycan during lens development.
abstract: BACKGROUND
  Adhesion molecules are known to be instructive for both development and differentiation. During lens differentiation, epithelial cells undergo vertical elongation, with the anterior and posterior tips of the elongating fiber cells sliding along the epithelium and capsule, respectively. These cellular processes are highly coordinated through cell adhesive interactions, actin cytoskeletal reorganization and contractile force generation. Alterations in extracellular matrix composition that interfere with these interactions can lead to defects that alter tissue morphogenesis and the state of differentiation. We have demonstrated that Equarin, which is a secreted molecule expressed in the equator region of the lens, plays an important role in chick lens fiber differentiation through fibroblast growth factor signaling.
  
  
  RESULTS
  Here, we explored the function of Equarin in chick lens cell adhesion. Equarin protein was expressed in the extracellular region of lens differentiating cells. We found that Equarin promoted lens cell adhesion through heparan sulfate proteoglycan. By biochemical analysis, we found that Equarin directly binds syndecan-3, which displayed a similar expression pattern to Equarin. Overexpression of Equarin resulted in altered actin localization.
  
  
  CONCLUSIONS
  Equarin is involved in cell adhesion during fiber differentiation and development.
authors.affiliation: Division of Developmental Neurobiology, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto, 860-8556, Japan.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Song
authors.forename: Yuya
authors.initials: Y
authors.lastname: Sato
authors.forename: Kiyotoshi
authors.initials: K
authors.lastname: Sekiguchi
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Kunimasa
authors.initials: K
authors.lastname: Ohta
mesh_terms: D000818:Animals; D019556:COS Cells; D002448:Cell Adhesion / Q000502:physiology*; D002642:Chick Embryo; D002522:Chlorocebus aethiops; D003599:Cytoskeleton / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007908:Lens, Crystalline / Q000196:embryology*; D008954:Models, Biological; D009024:Morphogenesis / Q000502:physiology*; D053670:Syndecan-3 / Q000378:metabolism
chemical_list: C448780:Ccdc80 protein, mouse; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D019812:Heparan Sulfate Proteoglycans; D036341:Intercellular Signaling Peptides and Proteins; D053670:Syndecan-3