Heat Shock Protein 27 (HSP27, Heat Shock Protein beta-1, HspB1, Heat Shock 27kD Protein, Stress-responsive Protein 27, SRP27, Estrogen-regulated 24kD Protein, 28kD Heat Shock Protein)

Hsp25 is the mouse homologue of the human Hsp27 protein, a member of the small heat shock protein family comprised of a diverse group of proteins from ~15 to>30kDa(1). The basic structure of most sHsps is a homologous and highly conserved amino acid sequence, \nwith an a-crystallin-domain at the C-terminus and the WD/EPF domain at the less conserved N-terminus. This N-terminus is essential for the development of high molecular oligomers (2, 3). Hsp27-oligomers consist of stable dimers formed by as many as 8-40 Hsp27 protein \nmonomers (4). The oligomerization status is connected with the chaperone activity: aggregates of large oligomers have high chaperone activity, whereas dimers have no chaperone activity (5). \nHSP27 is localized to the cytoplasm of unstressed cells but can redistribute to the nucleus in response to stress, where it may function to stabilize DNA and/or the nuclear membrane. It can be rapidly phosphorylated in response to physiological stimuli relevant to the cell type examined. Thus, hsp27 has been suggested to be an important intermediate in second essenger-mediated \nsignaling pathways (6). Other functions include chaperone activity (as mentioned above), thermo- tolerance in vivo, inhibition of apoptosis, and signal transduction. Specifically, in vitro, it acts as an ATP-independent chaperone by inhibiting protein aggregation and by stabilizing partially denatured proteins, which ensures refolding of the HSP70 complex. Hsp27 is also involved in the apoptotic signaling pathway because it interferes with the activation of cytochrome c/Apaf-1/dATP complex, thereby inhibiting the activation of procaspase- 9. It is also hypothesized that hsp27 may serve some role in cross-bridge formation between actin and myosin (7). And finally, Hsp27 is also thought to be involved in the process of cell differentiation. The up-regulation of Hsp27 correlates with the rate of phosphorylation and \nwith an increase of large oligomers. It is possible that Hsp27 may play a crucial role in termination of growth (8).\n\nApplications:\nSuitable for use in Immunofluorescence and Western Blot. Other applications not tested.\n\nRecommended Dilution:\nImmunofluorescence:1:200\nWestern Blot:1:5000\nOptimal dilutions to be determined by the researcher.\n\nStorage and Stability:\nMay be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.

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SPECIFICATIONS

Catalog Number

H1830-53G

Size

25ug

Applications

ICC, IF, IHC, IP, WB

Hosts

Mouse

Reactivities

Hum, Rat, Bov, Can, GP

Form

Supplied as a liquid in PBS in 0.09% sodium azide and 50% glycerol.

P Type

Mab

Purity

Purified by Protein G affinity chromatography.

Isotype

IgG1

References

1. Welch W.J. (1985) J Biol. Chem. 260: 3058-3062. 2. Kim K.K., Kim R., and Kim S. (1998) Nature 394(6693):595-599. 3. Van Montfort R., Slingsby C., and Vierling E. (2001) Addv Protein Chem. 59:105-56. 4. Ehrnsperger M., Graber S., Gaestel M. and Buchner J.(1997) EMBO J. 16: 221-229. \n5. Ciocca D.R., Oesterreich S., Chamness G.C., McGuire W.L., and Fugua S.A. (1993) J Natl Cancer Inst. 85 (19):1558-70. 6. Welsh M.J., Wu W., Parvinem M., and Gilmont R.R. (1996) Biol. Of Reprod. 55:141-151. \n7. Sarto C. Binnz P.A. and Mocarelli P. (2000) Electrophoresis. 21(6): 1218-26. 8. Arrigo A.P. (2005) J Cell Biochem. 94(2): 241-6. 9. Jia, Y. et al. (2001) J. Biol. Chem. 276(43):39911-39918.

Additional Info

Recognizes hsp25 and hsp27, and cross-reacts with alpha B crystallin. Species Crossreactivity: rat, bovine, canine, guinea pig, hamster.