Characterizing molecular diffusion in the lens capsule

Brian P. Danysh, Tapan P. Patel, Kirk J. Czymmek, David A. Edwards, Liyun Wang, Jayanti Pande, Melinda K. Duncan

Research output: Contribution to journalArticle

Abstract

The lens capsule compartmentalizes the cells of the avascular lens from other ocular tissues. Small molecules required for lens cell metabolism, such as glucose, salts, and waste products, freely pass through the capsule. However, the lens capsule is selectively permeable to proteins such as growth hormones and substrate carriers which are required for proper lens growth and development. We used fluorescence recovery after photobleaching (FRAP) to characterize the diffusional behavior of various sized dextrans (3, 10, 40, 150, and 250. kDa) and proteins endogenous to the lens environment (EGF, γD-crystallin, BSA, transferrin, ceruloplasmin, and IgG) within the capsules of whole living lenses. We found that proteins had dramatically different diffusion and partition coefficients as well as capsule matrix binding affinities than similar sized dextrans, but they had comparable permeabilities. We also found ionic interactions between proteins and the capsule matrix significantly influence permeability and binding affinity, while hydrophobic interactions had less of an effect. The removal of a single anionic residue from the surface of a protein, γD-crystallin [E107A], significantly altered its permeability and matrix binding affinity in the capsule. Our data indicated that permeabilities and binding affinities in the lens capsule varied between individual proteins and cannot be predicted by isoelectric points or molecular size alone.

Original languageEnglish (US)
Pages (from-to)228-236
Number of pages9
JournalMatrix Biology
Volume29
Issue number3
DOIs
StatePublished - Apr 1 2010
Externally publishedYes

Keywords

  • Basement membrane
  • Binding affinity
  • Diffusion coefficient
  • FRAP
  • Lens capsule
  • Partition coefficient
  • Permeabilitiy

ASJC Scopus subject areas

  • Molecular Biology

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  • Cite this

    Danysh, B. P., Patel, T. P., Czymmek, K. J., Edwards, D. A., Wang, L., Pande, J., & Duncan, M. K. (2010). Characterizing molecular diffusion in the lens capsule. Matrix Biology, 29(3), 228-236. https://doi.org/10.1016/j.matbio.2009.12.004