title: Functions of crystallins in and out of lens: roles in elongated and post-mitotic cells.
abstract: The vertebrate lens evolved to collect light and focus it onto the retina. In development, the lens grows through massive elongation of epithelial cells possibly recapitulating the evolutionary origins of the lens. The refractive index of the lens is largely dependent on high concentrations of soluble proteins called crystallins. All vertebrate lenses share a common set of crystallins from two superfamilies (although other lineage specific crystallins exist). The α-crystallins are small heat shock proteins while the β- and γ-crystallins belong to a superfamily that contains structural proteins of uncertain function. The crystallins are expressed at very high levels in lens but are also found at lower levels in other cells, particularly in retina and brain. All these proteins have plausible connections to maintenance of cytoplasmic order and chaperoning of the complex molecular machines involved in the architecture and function of cells, particularly elongated and post-mitotic cells. They may represent a suite of proteins that help maintain homeostasis in such cells that are at risk from stress or from the accumulated insults of aging.
authors.affiliation: Department of Biological Sciences, Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, London WC1E 7HX, UK. Electronic address: c.slingsby@mail.cryst.bbk.ac.uk.
authors.forename: Christine
authors.initials: C
authors.lastname: Slingsby
authors.affiliation: Section on Molecular Structure and Functional Genomics, National Eye Institute, Bg 6, Rm 106, National Institutes of Health, Bethesda, MD 20892-0608, USA.
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Wistow
mesh_terms: D000818:Animals; D048430:Cell Shape; D003459:Crystallins / Q000737:chemistry / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D007908:Lens, Crystalline / Q000166:cytology* / Q000378:metabolism*; D008938:Mitosis
chemical_list: D003459:Crystallins
keywords: Chaperone; Crystallins; Epithelial cell; Lens; Retina; Stress