Our long-term objective is to identify the molecular factors responsible for light scattering and opacification of the lens. Light scattering can be produced in the lens by the formation of protein aggregates, the condensation of proteins into coexisting protein-rich and protein-poor liquid phases and the condensation of proteins into crystalline solid phases. In previous years, we have identified various molecular mechanisms that produce such condensates, and thereby result in light scattering and opacification in gamma crystallin solutions in vitro. Some of these mechanisms are now known to be responsible for several human genetic cataracts. We now wish to extend our work by conducting investigations of the condensates formed by the beta crystallins. Moreover, with the extensive knowledge base of gamma crystallins, we also want to explore the thermodynamic and kinetic behavior of the mixtures of beta and gamma crystallins, in an effort to emulate more realistically the situation present in the lens cytoplasm. To achieve these objectives, we propose the following Specific Aims: 1. To determine the phase diagrams, and the kinetics of aggregation of aqueous solutions of recombinant human beta crystallins, and their naturally occurring mutant and truncated forms. 2. To explore the interactions between beta and gamma crystallins, by studying the phase-diagrams and kinetics of aggregation of solutions of beta and gamma crystallin mixtures. 3. To develop a theoretical description which can predict the phase diagrams, and the kinetics of aggregation for solutions of pure beta and gamma crystallins as well as their mixtures.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY005127-22
Application #
6770692
Study Section
Special Emphasis Panel (ZRG1-AED (01))
Program Officer
Liberman, Ellen S
Project Start
1983-05-01
Project End
2008-06-30
Budget Start
2004-07-01
Budget End
2005-06-30
Support Year
22
Fiscal Year
2004
Total Cost
$400,000
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Physics
Type
Schools of Arts and Sciences
DUNS #
001425594
City
Cambridge
State
MA
Country
United States
Zip Code
02139
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McManus, Jennifer J; Lomakin, Aleksey; Ogun, Olutayo et al. (2007) Altered phase diagram due to a single point mutation in human gammaD-crystallin. Proc Natl Acad Sci U S A 104:16856-61
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Pande, J; Berland, C; Broide, M et al. (1991) Suppression of phase separation in solutions of bovine gamma IV-crystallin by polar modification of the sulfur-containing amino acids. Proc Natl Acad Sci U S A 88:4916-20
Broide, M L; Berland, C R; Pande, J et al. (1991) Binary-liquid phase separation of lens protein solutions. Proc Natl Acad Sci U S A 88:5660-4
Siezen, R J; Coppin, C M; Kaplan, E D et al. (1989) Oxidative modifications to crystallins induced in calf lenses in vitro by hydrogen peroxide. Exp Eye Res 48:225-35
Siezen, R J; Hom, C; Kaplan, E D et al. (1988) Heterogeneity of gamma-crystallins from spiny dogfish (Squalus acanthias) eye lens. Exp Eye Res 46:81-93
Siezen, R J; Wu, E; Kaplan, E D et al. (1988) Rat lens gamma-crystallins. Characterization of the six gene products and their spatial and temporal distribution resulting from differential synthesis. J Mol Biol 199:475-90
Thomson, J A; Schurtenberger, P; Thurston, G M et al. (1987) Binary liquid phase separation and critical phenomena in a protein/water solution. Proc Natl Acad Sci U S A 84:7079-83

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