The function of alpha-crystallin in vision

The alpha-crystallins account for approximately one-third of the total solu ble protein in the lens, contributing to its refractive pourer. In addition , alpha-crystallin also has a chaperone-like function and thus can bind unf olding lens proteins. Alpha B-crystallin is also found outside the lens, ha ving an extensive tissue distribution. It is over-expressed in response to stresses of all kinds, where it is thought to serve a general protective fu nction. Recently, it has been shown in humans that naturally occurring poin t mutations in the alpha-crystallins result in a deficit in chaperone-like function, and cause cataracts as well as a desmin-related myopathy. This re view summarizes much of the past and current knowledge concerning the struc ture and functions of alpha-crystallin.