Technical Data
Endoplasmic Reticulum Protein 57 (ERp57, GRP58, PDIA3, Protein disulfide isomerase family A, member 3 [Homo sapiens], HGNC:4606, ERp60, ERp61, GRP57, HsT17083, P58, PI-PLC, 58kD microsomal protein, endoplasmic reticulum P58, glucose regulated protein, 58k
ERp57 (also known as Grp58), a member of the thioredoxin superfamily, is an ER protein with disulfide isomerase activity. It has been shown to increase after oncogenic transformation and to be a component of the MHC Class I peptide-loading complex.

The Grps are induced by glucose or oxygen deprivation and by chemical compounds which perturb protein trafficking and secretion or calcium homeostasis. It has been reported (2) that the microsomal carnitine palmitoyl-transferase (CPT) seemed to be the protein that had been described previously as Grp58 (3), also known as Erp57, Erp61 (4), and HIP-70 (hormone-induced protein-70) (5). It has since been established that Erp61 and Grp58 are the same protein (6). CPT has a nuclear localization signal (7) and has been localized in the nucleus (8). It has been speculated (1) that in the nuclear microenvironment, by acting as a CPT, this protein modulates the levels of acyl-CoA and carnitine, both of which have been implicated in the regulation of gene transcription (911). It is also known that protein acylation-deacylation is crucial for the proper functioning of certain proteins and that this requires acyl-CoA (12). Reportedly oestrogen and leutenzing-hormone-releaseing hormone induce this 54kD protein ~100 fold in the hippocampus region of the brain (13). The presence in this protein of an apparent oestrogen-binding domain (14) and of two thioredoxin active-site sequences, CGHC, were recognized previously. Proteins with one or more CGHC sequence are classified as members of the thioredoxin superfamily (15). It remains to be seen how the possible interaction of the oestrogen-binding and CGHC domain, together with the CPT activity, link the diverse apparent functions ascribed to this protein.

Suitable for use in Western Blot, Immunoprecipitation. Other applications not tested.

Recommended Dilution:
Western Blot (Colorimetric): 0.5ug/ml
Immunoprecipitation: 10ug/ml
Optimal dilutions to be determined by the researcher.

Positive Controls:
HeLa Heat Shocked Cell Lysate

Storage and Stability:
May be stored at 4C for short-term only. For long-term storage, store at -20C. Aliquots are stable for at least 12 months at -20C. 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.
MabIgG14E69Affinity Purified
50ug-20CBlue IceHumanMouse
Recombinant human ERp57 full length protein.
Purified by Protein G affinity chromatography.
Supplied as a liquid in PBS, pH 7.2, 25mM sodium chloride, 5mM sodium phosphate , 0.05mM PMSF, 50% glycerol.
Detects a ~58kD protein, corresponding to the apparent molecular mass of ERp57 on SDS-PAGE immunoblots, in samples from human, canine, porcine, hamster and monkey. There is no reactivity detected in mouse or rat cell lines.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.
1. Hirano, N., et al., (1994) Biochem. Biophys. Res. Commun. 204: 375-382. 2. Hughes, E.A., and Cresswell, P. (1998) Current Biology 8:709-712. 3. Murthy, M.S.R., and Pande, S.V. (1994) Biochem J. 304:31-34. 4. Murthy, M.S.R., and Pande, S.V. (1993) Mol. Cell. Biochem. 122:133-138. 5. Lee, A.S. (1981) J. Cell. Physiol. 106:119-125. 6. Mazzarella, R.A., et al., (1990) J. Biol. Chem. 265:1094-1101.
7. Kaplitt, M.G., et al., (1993) Endocrinology (Baltimore) 133:99-104. 8. Mazzarella, R.A., et al., (1994) Arch. Biochem. Biophys. 308:454-460. 9. Alteri, F., et al., (1993) Biochem. Biophys. Res. Commun. 194:992-1000. 10. Ohtani, H., et al., (1993) Histochemistry 100:423-429. 11. Henry, M.F., and Cronan, J.E., Jr. (1992) Cell 70:671-679. 12. DiRusso, C.C., Heimert, T.L., and Metzer, A.K. (1992) J. Biol. Chem. 267:8685-8691. 13. Roncero, C. and Goodridge, A. (1992) J. Biol. Chem. 267:14918-14927. 14. Camp, L.A. and Hoffmann, S.L. (1993) J. Biol. Chem. 268:22566-22574. 15. Mobbs, C.V., Fink, G., and Pfaff, D.W. (1990) Science 247:1477-1479. 16. Barker, W.C., et al., (1990) Science 249:566-567. 17. Nigam, S.K., et al., (1994) J. Biol. Chem. 269:1744-1749.