title: Beta-1 integrin is important for the structural maintenance and homeostasis of differentiating fiber cells.
abstract: β1-Integrin is a heterodimeric transmembrane protein that has roles in both cell-extra-cellular matrix and cell-cell interactions. Conditional deletion of β1-integrin from all lens cells during embryonic development results in profound lens defects, however, it is less clear whether this reflects functions in the lens epithelium alone or whether this protein plays a role in lens fibers. Thus, a conditional approach was used to delete β1-integrin solely from the lens fiber cells. This deletion resulted in two distinct phenotypes with some lenses exhibiting cataracts while others were clear, albeit with refractive defects. Analysis of "clear" conditional knockout lenses revealed that they had profound defects in fiber cell morphology associated with the loss of the F-actin network. Physiological measurements found that the lens fiber cells had a twofold increase in gap junctional coupling, perhaps due to differential localization of connexins 46 and 50, as well as increased water permeability. This would presumably facilitate transport of ions and nutrients through the lens, and may partially explain how lenses with profound structural abnormalities can maintain transparency. In summary, β1-integrin plays a role in maintaining the cellular morphology and homeostasis of the lens fiber cells.
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States.
authors.forename: David A
authors.initials: DA
authors.lastname: Scheiblin
authors.affiliation: Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, New York, NY 11794-8661, United States.
authors.forename: Junyuan
authors.initials: J
authors.lastname: Gao
authors.affiliation: Delaware Biotechnology Institute, University of Delaware, Newark, DE 19716, United States.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Caplan
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States.
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Simirskii
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States.
authors.forename: Kirk J
authors.initials: KJ
authors.lastname: Czymmek
authors.affiliation: Department of Physiology and Biophysics, State University of New York at Stony Brook, Stony Brook, New York, NY 11794-8661, United States.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Mathias
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, DE 19716, United States. Electronic address: duncanm@udel.edu.
authors.forename: Melinda K
authors.initials: MK
authors.lastname: Duncan
mesh_terms: D000199:Actins / Q000378:metabolism; D000483:Alleles; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D017630:Connexins / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D006706:Homeostasis; D019012:Integrin beta1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D007908:Lens, Crystalline / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008855:Microscopy, Electron, Scanning / Q000379:methods; D010641:Phenotype
chemical_list: D000199:Actins; D017630:Connexins; D019012:Integrin beta1
keywords: Connexins; Cytoskeleton; Differentiation; Lens; Lens fiber cells; β1-Integrin