title: A role for lengsin, a recruited enzyme, in terminal differentiation in the vertebrate lens.
abstract: Lengsin is an eye lens-specific member of the glutamine synthetase (GS) superfamily. Lengsin has no GS activity, suggesting that it has a structural rather than catalytic role in lens. In situ hybridization and immunofluorescence showed that lengsin is expressed in terminally differentiating secondary lens fiber cells. Yeast two-hybrid (Y2H) and recombinant protein experiments showed that full-length lengsin can bind the 2B filament region of vimentin. In affinity chromatography, lengsin also bound the equivalent region of CP49 (BFSP2; phakinin), a related intermediate filament protein specific to the lens. Both the vimentin and CP49 2B fragments bound lengsin in surface plasmon resonance spectroscopy with fast association and slow dissociation kinetics. Lengsin expression correlates with a transition zone in maturing lens fiber cells in which cytoskeleton is reorganized. Lengsin and lens intermediate filament proteins co-localize at the plasma membrane in maturing fiber cells. This suggests that lengsin may act as a component of the cytoskeleton itself or as a chaperone for the reorganization of intermediate filament proteins during terminal differentiation in the lens.
authors.affiliation: National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Keith
authors.initials: K
authors.lastname: Wyatt
authors.forename: Chun
authors.initials: C
authors.lastname: Gao
authors.forename: Jen-Yue
authors.initials: JY
authors.lastname: Tsai
authors.forename: Robert N
authors.initials: RN
authors.lastname: Fariss
authors.forename: Sugata
authors.initials: S
authors.lastname: Ray
authors.forename: Graeme
authors.initials: G
authors.lastname: Wistow
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D005974:Glutamate-Ammonia Ligase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D007382:Intermediate Filaments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D007908:Lens, Crystalline / Q000166:cytology / Q000201:enzymology*; D051379:Mice; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020349:Surface Plasmon Resonance; D020798:Two-Hybrid System Techniques; D014746:Vimentin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D005136:Eye Proteins; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D014746:Vimentin; C529156:lengsin protein, mouse; D005974:Glutamate-Ammonia Ligase