A role for lengsin, a recruited enzyme, in terminal differentiation in the vertebrate lens.
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.
Wyatt
Keith
K
National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Gao
Chun
C
Tsai
Jen-Yue
JY
Fariss
Robert N
RN
Ray
Sugata
S
Wistow
Graeme
G
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
D005136:Eye Proteins; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D014746:Vimentin; C529156:lengsin protein, mouse; D005974:Glutamate-Ammonia Ligase