CRYAB Antibody

Background:

Crystallins are separated into two classes:taxon-specific, or enzyme, and ubiquitous. The latter classconstitutes the major proteins of vertebrate eye lens and maintainsthe transparency and refractive index of the lens. Since lenscentral fiber cells lose their nuclei during development, thesecrystallins are made and then retained throughout life, making themextremely stable proteins. Mammalian lens crystallins are dividedinto alpha, beta, and gamma families; beta and gamma crystallinsare also considered as a superfamily. Alpha and beta families arefurther divided into acidic and basic groups. Seven protein regionsexist in crystallins: four homologous motifs, a connecting peptide,and N- and C-terminal extensions. Alpha crystallins are composed oftwo gene products: alpha-A and alpha-B, for acidic and basic,respectively. Alpha crystallins can be induced by heat shock andare members of the small heat shock protein (sHSP also known as theHSP20) family. They act as molecular chaperones although they donot renature proteins and release them in the fashion of a truechaperone; instead they hold them in large soluble aggregates.Post-translational modifications decrease the ability to chaperone.These heterogeneous aggregates consist of 30-40 subunits; thealpha-A and alpha-B subunits have a 3:1 ratio, respectively. Twoadditional functions of alpha crystallins are an autokinaseactivity 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 isexpressed widely in many tissues and organs. Elevated expression ofalpha-B crystallin occurs in many neurological diseases; a missensemutation cosegregated in a family with a desmin-related myopathy.