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Protein CRYBB2 PDB 1bd7.png
Available structures
PDB Ortholog search: PDBe RCSB
Aliases CRYBB2, CCA2, CRYB2, CRYB2A, CTRCT3, D22S665, crystallin beta B2
External IDs MGI: 88519 HomoloGene: 420 GeneCards: CRYBB2
RNA expression pattern
PBB GE CRYBB2 206777 s at fs.png

PBB GE CRYBB2 206778 at fs.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 22: 25.22 – 25.23 Mb Chr 5: 113.06 – 113.07 Mb
PubMed search [1] [2]
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Beta-crystallin B2 is a protein that in humans is encoded by the CRYBB2 gene.[3][4][5]


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-terminal and C-terminal extensions. Beta-crystallins, the most heterogeneous, differ by the presence of the C-terminal extension (present in the basic group, none in the acidic group). Beta-crystallins form aggregates of different sizes and are able to self-associate to form dimers or to form heterodimers with other beta-crystallins. This gene, a beta basic group member, is part of a gene cluster with beta-A4, beta-B1, and beta-B3. A chain-terminating mutation was found to cause type 2 cerulean cataracts.[5]


CRYBB2 has been shown to interact with Hsp27,[6] CRYGC,[6] CRYAA[6] and CRYAB.[6]


  1. ^ "Human PubMed Reference:". 
  2. ^ "Mouse PubMed Reference:". 
  3. ^ Litt M, Carrero-Valenzuela R, LaMorticella DM, Schultz DW, Mitchell TN, Kramer P, Maumenee IH (Jul 1997). "Autosomal dominant cerulean cataract is associated with a chain termination mutation in the human beta-crystallin gene CRYBB2". Hum Mol Genet. 6 (5): 665–8. doi:10.1093/hmg/6.5.665. PMID 9158139. 
  4. ^ Chambers C, Russell P (Dec 1993). "Sequence of the human lens beta B2-crystallin-encoding cDNA". Gene. 133 (2): 295–9. doi:10.1016/0378-1119(93)90655-M. PMID 8224918. 
  5. ^ a b "Entrez Gene: CRYBB2 crystallin, beta B2". 
  6. ^ a b c d Fu L, Liang JJ (February 2002). "Detection of protein-protein interactions among lens crystallins in a mammalian two-hybrid system assay". J. Biol. Chem. 277 (6): 4255–60. doi:10.1074/jbc.M110027200. PMID 11700327. 

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