Entrez Summary: 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. Post-translational modifications decrease the ability to chaperone. 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. Defects in this gene cause autosomal dominant congenital cataract (ADCC). [provided by RefSeq, Jan 2014].
UniProt Summary: Contributes to the transparency and refractive index of the lens. Has chaperone-like activity, preventing aggregation of various proteins under a wide range of stress conditions. {ECO:0000269|PubMed:22120592}.
Pfam DomainsGO Terms
Pfam Domains
HSP20
Crystallin
GO Terms
structural constituent of eye lens
protein refolding
negative regulation of intracellular transport
unfolded protein binding
protein stabilization
visual perception
sensory perception of light stimulus
protein folding
regulation of protein stability
protein homooligomerization
regulation of intracellular transport
negative regulation of transport
protein complex oligomerization
negative regulation of apoptotic process
negative regulation of programmed cell death
regulation of cellular localization
sensory perception
negative regulation of cell death
identical protein binding
nervous system process
regulation of apoptotic process
protein-containing complex assembly
regulation of programmed cell death
regulation of cell death
protein-containing complex subunit organization
regulation of transport
system process
CRISPR Data
Compound HitMost Correlated Genes in ChemogenomicsTissues where Essential in the Avana Dataset (DepMap 20Q1)