CRYAB

Also known as CMD1II, CRYA2, CTPP2, CTRCT16, HEL-S-101, HSPB5, MFM2, crystallin alpha B

Alpha-crystallin B chain is a protein that in humans is encoded by the CRYAB gene. It is part of the small heat shock protein family and functions as molecular chaperone that primarily binds misfolded proteins to prevent protein aggregation, as well as inhibit apoptosis and contribute to intracellular architecture. Post-translational modifications decrease the ability to chaperone. Mutations in CRYAB cause different cardiomyopathies, skeletal myopathies mainly myofibrillar myopathy, and also cataracts. In addition, defects in this gene/protein have been associated with cancer and neurodegenera

Gene data

CRYAB

Name: crystallin alpha B
Type: protein-coding
Position: 111,908,564–111,923,722 (−)
Aliases: CMD1II, CRYA2, CTPP2, CTRCT16, HEL-S-101, HSPB5, MFM2, MFM2A, MFM2B
Ensembl: ENSG00000109846
RefSeq RNA: NM_001289807.1, NM_001289808.2, NM_001330379.1, NM_001368245.1, NM_001368246.1
RefSeq protein: NP_001276736.1, NP_001276737.1, NP_001317308.1, NP_001355174.1, NP_001355175.1

Mammalian lens crystallins are divided into alpha, beta, and gamma families. 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 (HSP20) family. They act as molecular chaperones although they do not renature proteins and release them in the fashion of a true chaperone; instead they hold them in large soluble aggregates. These heterogeneous aggregates consist of 30-40 subunits; the alpha-A and alpha-B subunits have a 3:1 ratio, respectively. Two additional functions of alpha crystallins are an autokinase activity and participation in the intracellular architecture. The encoded protein has been identified as a moonlighting protein based on its ability to perform mechanistically distinct functions. Alpha-A and alpha-B gene products are differentially expressed; alpha-A is preferentially restricted to the lens and alpha-B is expressed widely in many tissues and organs. Elevated expression of alpha-B crystallin occurs in many neurological diseases; a missense mutation cosegregated in a family with a desmin-related myopathy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2019].