Antibodies to alpha and beta Crystallins - FocusOn 038

Introduction: The α-crystallin superfamily and βγ-crystallins compose the major superfamily of proteins present in the crystalline lens. Beta- and gamma-crystallins are similar in sequence, structure and domains topology, and thus have been grouped together as a protein superfamily called βγ-Crystallins.

Alpha-crystallins, composed of alpha A (~19 kDa) and alpha B (~19.2 kDa) subunits, are major water-soluble proteins accounting for almost 50% of total protein in the mammalian transparent eye lens and they are also found in a variety of other tissues (1). Alpha-crystallins are also referred to as small heat shock proteins, since they are induced by increased temperature in a variety of organisms (2). The alpha-crystallins have sequence homology as well as structural and functional similarities with the small Hsp´s such as Hsp25/27 (3). Most alpha-crystallins have four common structural and functional features: (1) molecular weight between 12 and 43kDa; (2) the formation of large oligomeric complexes composed of alpha A-crystallin, alpha B-crystallin and Hsp25/27; (3) the moderately conserved alpha-crystallin domain in the central region of the protein; and (4) molecular chaperone activity (2,4). The alpha-crystallin domain, comprised of approximately 90 residues, is bound by variable N-terminal and C-terminal extensions and is involved in oligomer assembly. Oligomers can reach 800kDa or more and are dynamic, exhibiting subunit exchanges and organizational plasticity, possibly leading to functional diversity. Phosphorylation of serine residues occurs during development and in response to stress, and usually decreases oligomer size (4). Chaperone activity requires, and is modulated by oligomerization and is limited to binding unfolded intermediates to prevent irreversible aggregation (2,4). Other proposed functions include a role in membrane stabilization (2) and modulation of intermediate filament organization during physiological stress and neurodegenerative disease (5).

Antibody Tools for the Detection of Crystallins

Acris Antibodies offers an antibody panel to both alpha-crystallin isoforms and to beta-crystallin; antibodies to the phosphorylated forms of alpha B-crystallin are also available. These monoclonal or polyclonal antibodies can be used in different immunological detection methods like ELISA, Western blotting or immunohistochemistry.

Literature

1. Augusteyn, R. C., et al. (1992) Exp. Eye Res. 54:219-228
2. Narberhaus, F. (2002) Microbiol. Mol. Biol. Rev. 66(1): 64-93.
3. Merck, K. B.,et al. (1993) J. Biol. Chem. 268: 1046-1052.
4. MacRae, T.H. (2000) Cell Mol. Life Sci. 57(6): 899-913.
5. Head, M.W. and Goldman, J.E. (2000) Neuropathol. Appl. Neurobiol. 26(4): 304-312.
6. van Noort, J.M., et al., 1995, Nature, 375, 798-801
7. Fujii N., et al., (2003) Mol. Vis. 9: 915-22
8. Laksanalamai P., et al., (2004) Extremophiles 8: 1-11
9. De S, Rabin DM, Salero E, Lederman PL, Temple S, Stern JH. (2007) Arch. Ophthalmol. 125(5): 641-5.
10. Ghosh JG, Shenoy AK, Clark JI. (2007) Biochemistry 46(21): 6308-17

Available Antibody Panel to Crystallin
Anti alpha Crystallin, Crystallin alpha A antibody, Crystallin alpha B antibody; anti beta Crystallin, Crystallin beta H and Crystallin beta L antibody