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Crystallin, beta B2
Protein CRYBB2 PDB 1bd7.png
PDB rendering based on 1bd7.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols CRYBB2 ; CCA2; CRYB2; CRYB2A; CTRCT3; D22S665
External IDs OMIM123620 MGI88519 HomoloGene420 GeneCards: CRYBB2 Gene
RNA expression pattern
PBB GE CRYBB2 206777 s at tn.png
PBB GE CRYBB2 206778 at tn.png
More reference expression data
Species Human Mouse
Entrez 1415 12961
Ensembl ENSG00000244752 ENSMUSG00000042240
UniProt P43320 P62696
RefSeq (mRNA) NM_000496 NM_007773
RefSeq (protein) NP_000487 NP_031799
Location (UCSC) Chr 22:
25.62 – 25.63 Mb
Chr 5:
113.06 – 113.07 Mb
PubMed search [1] [2]

Beta-crystallin B2 is a protein that in humans is encoded by the CRYBB2 gene.[1][2][3]


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.[3]


CRYBB2 has been shown to interact with Hsp27,[4] CRYGC,[4] CRYAA[4] and CRYAB.[4]


  1. ^ 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. 
  2. ^ 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. 
  3. ^ a b "Entrez Gene: CRYBB2 crystallin, beta B2". 
  4. ^ 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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