Lens Biology and Biochemistry

J. Fielding Hejtmancik, S. Amer Riazuddin, Rebecca McGreal, Wei Liu, Ales Cvekl, Alan Shiels

Research output: Chapter in Book/Report/Conference proceedingConference contribution

21 Scopus citations

Abstract

The primary function of the lens resides in its transparency and ability to focus light on the retina. These require both that the lens cells contain high concentrations of densely packed lens crystallins to maintain a refractive index constant over distances approximating the wavelength of the light to be transmitted, and a specific arrangement of anterior epithelial cells and arcuate fiber cells lacking organelles in the nucleus to avoid blocking transmission of light. Because cells in the lens nucleus have shed their organelles, lens crystallins have to last for the lifetime of the organism, and are specifically adapted to this function. The lens crystallins comprise two major families: the βγ-crystallins are among the most stable proteins known and the α-crystallins, which have a chaperone-like function. Other proteins and metabolic activities of the lens are primarily organized to protect the crystallins from damage over time and to maintain homeostasis of the lens cells. Membrane protein channels maintain osmotic and ionic balance across the lens, while the lens cytoskeleton provides for the specific shape of the lens cells, especially the fiber cells of the nucleus. Perhaps most importantly, a large part of the metabolic activity in the lens is directed toward maintaining a reduced state, which shelters the lens crystallins and other cellular components from damage from UV light and oxidative stress. Finally, the energy requirements of the lens are met largely by glycolysis and the pentose phosphate pathway, perhaps in response to the avascular nature of the lens. Together, all these systems cooperate to maintain lens transparency over time.

Original languageEnglish (US)
Title of host publicationMolecular Biology of Eye Disease, 2015
EditorsJohn M. Nickerson, J. Fielding Hejtmancik
PublisherElsevier B.V.
Pages169-201
Number of pages33
ISBN (Print)9780128010594
DOIs
StatePublished - Jan 1 2015

Publication series

NameProgress in Molecular Biology and Translational Science
Volume134
ISSN (Print)1877-1173
ISSN (Electronic)1878-0814

Keywords

  • Crystallins
  • Lens
  • Membrane proteins
  • Transparency

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology

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    Hejtmancik, J. F., Riazuddin, S. A., McGreal, R., Liu, W., Cvekl, A., & Shiels, A. (2015). Lens Biology and Biochemistry. In J. M. Nickerson, & J. F. Hejtmancik (Eds.), Molecular Biology of Eye Disease, 2015 (pp. 169-201). (Progress in Molecular Biology and Translational Science; Vol. 134). Elsevier B.V.. https://doi.org/10.1016/bs.pmbts.2015.04.007