a-crystallin b chain

α Crystallin B Chain (CRYAB) is a cytoplasmic protein that belongs to the small heat shock protein (HSP20) family. Alpha crystallins 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 also known as the HSP20) family. Alpha crystallins acts as molecular chaperones and hold them in in large soluble aggregates. CRYAB is expressed widely in many tissues and organs. It may contribute to the transparency and refractive index of the lens. The deficiency of CRYAB is the cause of myopathy myofibrillar type 2 (MFM2) and cataract posterior polar type 2 (CTPP2).

Alpha-Crystallin A Chain (CRYAA) belongs to the small heat shock protein (HSP20) family and can be induced by heat shock. The expression of CRYAA is preferentially restricted to the lens cell. CRYAA may contribute to the transparency and refractive index of the lens. CRYAA has chaperone-like activity, preventing aggregation of various proteins under a wide range of stress conditions. Two additional functions of CRYAA are an autokinase activity and participation in the intracellular architecture.

Heat shock protein beta-8 (HSPB8) belongs to the small heat shock protein (HSP20) family. This protein can be inducted by 17-beta-estradiol, and is predominantly expressed in skeletal muscle and heat, mainly located in the cytoplasm and nucleus. HSPB8 usually exists in monomer, it can interact with HSPB1 and DNAJB6. HSPB8 displays temperature-dependent chaperone activity，appears to be involved in regulation of cell proliferation, apoptosis, and carcinogenesis, and mutations in this gene have been associated with different neuromuscular diseases, including Charcot-Marie-Tooth disease.