Alpha-crystallins, a major protein of the ocular lens, are thought to play a role in maintaining lens transparency, which are composed of two gene products alpha-A and alpha-B, for acidic and basic, respectively. alpha-crystallins can be induced by heat shock and are members of the small heat shock protein (sHSP). They act as molecular chaperones and hold unfolded or misfolded proteins in large, water-soluble low molecular weight aggregates. These heterogeneous aggregates consist of 30-40 subunits of alpha-crystallins, and the alpha-A and alpha-B subunits have a 3:1 ratio, respectively. Two additional functions of alpha-crystallins are an autokinase activity and the participation in the intracellular architecture.