CRYAB
| Gene Ontology | |
|---|---|
| Molecular function | • structural constituent of eye lens • protein binding • microtubule binding • protein homodimerization activity • metal ion binding • unfolded protein binding |
| Cellular component | • nucleus • cytoplasm • mitochondrion • Golgi apparatus • cytosol • plasma membrane • cell surface • microtubule cytoskeleton • Z disc • actin filament bundle |
| Biological process | • response to hypoxia • lens development in camera-type eye • glucose metabolic process • protein folding • muscle contraction • tubulin complex assembly • muscle organ development • aging • negative regulation of gene expression • negative regulation of cell growth • microtubule polymerization or depolymerization • response to estradiol stimulus • negative regulation of intracellular transport • response to hydrogen peroxide • negative regulation of apoptotic process • negative regulation of cysteine-type endopeptidase activity involved in apoptotic process • protein homooligomerization • stress-activated MAPK cascade • apoptotic process involved in morphogenesis • negative regulation of reactive oxygen species metabolic process |
| Sources: Amigo / QuickGO | |
111.78 – 111.79 Mb
50.75 – 50.76 Mb
Alpha-crystallin B chain is a protein that in humans is encoded by the CRYAB gene.
Crystallins are separated into two classes: taxon-specific, or enzyme, and ubiquitous. The latter class constitutes the major proteins of vertebrate eye lens and maintains the transparency and refractive index of the lens. Since lens central fiber cells lose their nuclei during development, these crystallins are made and then retained throughout life, making them extremely stable proteins. Mammalian lens crystallins are divided into alpha, beta, and gamma families; beta and gamma crystallins are also considered as a superfamily. Alpha and beta families are further divided into acidic and basic groups.
Seven protein regions exist in crystallins: four homologous motifs, a connecting peptide, and N- and C-terminal extensions. 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. 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. 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.
Read more about CRYAB: Interactions