HspB4 Antibody - #DF8933

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. Required for the correct formation of lens intermediate filaments as part of a complex composed of BFSP1, BFSP2 and CRYAA.

O-glycosylated; contains N-acetylglucosamine side chains.

Deamidation of Asn-101 in lens occurs mostly during the first 30 years of age, followed by a small additional amount of deamidation (approximately 5%) during the next approximately 38 years, resulting in a maximum of approximately 50% deamidation during the lifetime of the individual.

Phosphorylation on Ser-122 seems to be developmentally regulated. Absent in the first months of life, it appears during the first 12 years of human lifetime. The relative amount of phosphorylated form versus unphosphorylated form does not change over the lifetime of the individual.

Acetylation at Lys-70 seems to increase chaperone activity.

Undergoes age-dependent proteolytical cleavage at the C-terminus. Alpha-crystallin A(1-172) is the most predominant form produced most rapidly during the first 12 years of age and after this age is present in approximately 50% of the lens molecules.

Cytoplasm. Nucleus.
Note: Translocates to the nucleus during heat shock and resides in sub-nuclear structures known as SC35 speckles or nuclear splicing speckles.

Expressed in eye lens.

Heteropolymer composed of three CRYAA and one CRYAB subunits. Inter-subunit bridging via zinc ions enhances stability, which is crucial as there is no protein turn over in the lens. Can also form homodimers and higher homooligomers (via C-terminus). Part of a complex required for lens intermediate filament formation composed of BFSP1, BFSP2 and CRYAA.

Belongs to the small heat shock protein (HSP20) family.