title: The human crystallin gene families.
abstract: Crystallins are the abundant, long-lived proteins of the eye lens. The major human crystallins belong to two different superfamilies: the small heat-shock proteins (α-crystallins) and the βγ-crystallins. During evolution, other proteins have sometimes been recruited as crystallins to modify the properties of the lens. In the developing human lens, the enzyme betaine-homocysteine methyltransferase serves such a role. Evolutionary modification has also resulted in loss of expression of some human crystallin genes or of specific splice forms. Crystallin organization is essential for lens transparency and mutations; even minor changes to surface residues can cause cataract and loss of vision.
authors.affiliation: Section on Molecular Structure and Functional Genomics, National Eye Institute, National Institutes of Health, Bethesda, MD 20892-0608, USA. graeme@helix.nih.gov
authors.forename: Graeme
authors.initials: G
authors.lastname: Wistow
mesh_terms: D050940:Betaine-Homocysteine S-Methyltransferase / Q000235:genetics / Q000378:metabolism; D002386:Cataract / Q000235:genetics / Q000503:physiopathology; D003459:Crystallins / Q000235:genetics* / Q000378:metabolism; D050888:Heat-Shock Proteins, Small / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007908:Lens, Crystalline / Q000378:metabolism; D005810:Multigene Family; D009154:Mutation; D038203:alpha-Crystallin B Chain / Q000235:genetics* / Q000378:metabolism
chemical_list: C511246:CRYAA protein, human; C059215:CRYAB protein, human; D003459:Crystallins; D050888:Heat-Shock Proteins, Small; D038203:alpha-Crystallin B Chain; D050940:Betaine-Homocysteine S-Methyltransferase