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G. J. Wistow, K. Wyatt, C. Gao, J.-Y. Tsai, R. Fariss, S. Ray, C. Slingsby, E. Orlova, L. Dong; Lengsin, a Recruited Enzyme, Associates With Cytoskeleton in Lens Fiber Cell Terminal Differentiation. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1526.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the structure and function of Lengsin, a recently discovered major protein of the vertebrate eye lens.
Recombinant protein expression, yeast 2-hybrid analysis, surface plasmon resonance, electron microscopy, immunofluorescence, ‘knock out’ mouse.
Lengsin is lens-specific and highly conserved in vertebrate evolution, although it also shows taxon-specific differences in exon usage. It is a member of a family of class I glutamine synthetases (GS) with a 12-mer structure similar to that of prokaryotic GS but has lost enzyme function. Lengsin is expressed in terminally differentiating secondary lens fiber cells in adult lens. It can bind the lens intermediate filament proteins vimentin and CP49 and localizes with them at the fiber cell plasma membrane. Co-expressed lengsin and a filament region of vimentin associate in solution and are being examined for complex structure by CryoEM. The Lengsin gene has been deleted in mice and preliminary observations suggest defects in fiber cell packing.
Lengsin is a lone vertebrate survivor of an ancient group of enzymes. It appears to have been recruited to a highly specialized structural role in the lens in which its expression marks the terminal differentiation of secondary fiber cells. Lengsin associates with lens intermediate filament proteins, including beaded filaments, suggesting that it may be involved in organizing the architecture of fiber cells as they lose organelles and form tightly interdigitated cell contacts.
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