Heat Shock Protein 27, phosphorylated (Ser82) (HSP27)

Human Hsp27 belongs to the phylogenically conserved small heat shock protein (smHsp) family, which includes mouse Hsp25, alphaA-crystallins and alphaB-crystallins. Members of this protein superfamily from the animal, plant and microbiotic kingdoms share the so-called a-crystallin domain of approximately 90 amino acid residues which is bounded by variable N- and C-terminal extensions 1). Hsp27 is expressed constitutively in many tissues and its expression is increased to high levels after various types of stress including elevated temperatures, toxic metals, drugs and oxidants. Hsp27 is believed to exist mainly as oligomers of as many as 8-40 of Hsp27 protein monomers in cells and data suggest that these large oligomers have a chaperone-like activity by serving as a site where unfolding proteins may bind until ATP and Hsp70-dependent refolding can occur (2). Hsp27 is phosphorylated on three phosphorylation sites (Ser15, Ser78 and Ser82) by protein kinases including MAPKAP kinase 2/3 and the stress-activated protein kinase SAPK2 (p38) (3,4). Studies on cells stimulated by a variety of mitogenic and stress factors suggest that phosphorylation of Hsp27 occurs as an early prominent event and that phosphorylation induced changes in the ultrastructure of Hsp27 may regulate its biochemical activities. The state of phosphorylation and oligomerization of Hsp27 may regulate microfilament organization as shown by studies demonstrating that only the nonphosphorylated lower molecular weight forms of Hsp27 bind actin barbed ends and inhibit polymerization (5). Hsp27 is believed to protect cells by enhancing cellular glutathione levels as indicated by elevated glutathione levels in cells overexpressing Hsp27. Studies using wild-type Hsp27 and mutants in which the serine phosphorylation sites were mutated to alanines, glycines or aspartates, demonstrate that cellular glutathione levels depend on the oligomerization of Hsp27 with only the large oligomeric forms of Hsp27 capable of protecting cells by enhancing glutathione levels (6).\n\nApplications:\nSuitable for use in Western Blotting, Immunoprecipitation. Other applications not tested.\n\nRecommended Dilution:\nWestern Blot: 1:2000\nImmunoprecipitation: 1:100\n \nOptimal dilutions to be determined by the researcher.\n\nStorage and Stability:\nMay be stored at 4 degrees C for short-term only. For long-term storage and to avoid repeated freezing and thawing, add glycerol (40-50%)aliquot and store at -20 degrees C. Aliquots are stable for at least 12 months at -20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

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SPECIFICATIONS

Catalog Number

H1830-52L

Size

25ul

Applications

IP, WB

Hosts

Rabbit

Reactivities

Hum, Rat, Bov, Can, GP, NHP, Prc, Sheep

Form

Supplied as a liquid in PBS, pH 7.2, 0.1mM PMSF.

P Type

Pab

Purity

Purified by immunoaffinity chromatography.

References

1. MacRae, T.H (2000) Cell Mol. Life Sci. 57: 899-913.\n2. Ehrnsperger, M., Graber, S., Gaestel, M. and Buchner, J. (1997) EMBO J. 16: 221-229\n3. Maizels, E.T., Peters, C.A., Kline, M., Cutler, Jr., R.E., Shanmugam, M. and Hunzicker- Dunn, M. (1998) Biochem. J. 332: 703-712.\n4. Butt, E., Immler, D., Meyer, H.E., Kotlyarov, A., Laab, K. and Gaestel, M (2001) J. Biol. Chem. 276: 7108-7113\n5. Benndorf, R., Hayess, K., Ryazantsev, S., Wieske, M., Behlke, J and Lutsch, G. (1994) J. Biol. Chem. 269: 20780-20784 \n6. Mehlen, P., Hickey, E., Weber, L. A. and Arrigo, A-P. (1997) Biochem. Biophys. Res. Commun. 241:187-192

Additional Info

Specific for phosphorylated Hsp27 (Ser82) and does not exhibit reactivity with non-phosphorylated Hsp27. Specificity for phospho-Hsp27 was demonstrated in peptide \ncompetition studies with phosphorylated and non-phosphorylated peptides. Detects an ~27kD protein, corresponding to the apparent molecular mass of phosphorylated Hsp27 (Ser82) on SDS-PAGE Western Blots.\nSpecies reactivity: Human, rat, bovine, canine, guinea pig, hamster, monkey, porcine, sheep.