Revision 1

#9956Store at -20C

1 Kit

(7 x 20 microliters)

Cell Signaling Technology

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For Research Use Only. Not for Use in Diagnostic Procedures.
Product Includes Product # Quantity Mol. Wt Isotype/Source
BiP (C50B12) Rabbit mAb 3177 20 µl 78 kDa Rabbit IgG
Calnexin (C5C9) Rabbit mAb 2679 20 µl 90 kDa Rabbit IgG
Ero1-Lα Antibody 3264 20 µl 60 kDa Rabbit 
IRE1α (14C10) Rabbit mAb 3294 20 µl 130 kDa Rabbit IgG
PDI (C81H6) Rabbit mAb 3501 20 µl 57 kDa Rabbit 
CHOP (L63F7) Mouse mAb 2895 20 µl 27 kDa Mouse IgG2a
PERK (D11A8) Rabbit mAb 5683 20 µl 140 kDa Rabbit IgG
Anti-rabbit IgG, HRP-linked Antibody 7074 100 µl Goat 
Anti-mouse IgG, HRP-linked Antibody 7076 100 µl Horse 

Please visit for individual component applications, species cross-reactivity, dilutions, protocols, and additional product information.


The ER Stress Sampler Kit contains reagents to investigate ER stress within the cell. The kit contains enough primary and secondary antibodies to perform two Western blot experiments per primary antibody.


Supplied in 10 mM sodium HEPES (pH 7.5), 150 mM NaCl, 100 µg/ml BSA, 50% glycerol and less than 0.02% sodium azide. Store at –20°C. Do not aliquot the antibody.


Secretory and transmembrane proteins are synthesized on polysomes and translocate into the endoplasmic reticulum (ER) where they are often modified by the formation of disulfide bonds, amino-linked glycosylation and folding. The ER contains a pool of molecular chaperone proteins including calnexin, BiP and protein disulfide isomerase (PDI). Calnexin is an ER membrane, calcium-binding protein that retains newly synthesized glycoproteins inside the ER to ensure proper folding and quality control (1,2). Irregular protein folding within the ER increases BiP synthesis, which binds misfolded proteins to prevent them from forming aggregates and to assist them to refold properly (3).
PDI catalyzes the formation and isomerization of disulfide bonds required for a protein to reach its native state (4). Studies have found that the resident ER protein endoplasmic oxidoreductin-1 (Ero1) provides oxidizing potential to the ER in Saccharomyces cerevisiae (5). Ero1-Lα is an ER membrane-associated N-glycoprotein that promotes oxidative protein folding (6). Disruptions of ER homeostasis leads to the accumulation of unfolded proteins. The ER has developed an adaptive mechanism called the unfolded protein response (UPR) to counteract compromised protein folding (7). This is regulated by proteins such as the membrane-bound transcription factor protease site 2 (MBTPS2) and the serine/threonine kinase IRE1 (8-12). The PERK eIF2α kinase is an ER resident transmembrane protein that couples ER stress signals to translation inhibition. ER stress increases PERK activity, which phosphorylates eIF2α to reduce protein translation. PERK activation during ER stress correlates with autophosphorylation of its cytoplasmic kinase domain (13,14). Phosphorylation of PERK at Thr980 can serve as a marker for its activation status.
During ER stress, the level of CHOP expression is elevated and CHOP functions to mediate programmed cell death (15).

  1. Bergeron, J.J. et al. (1994) Trends Biochem. Sci. 19, 124-128.
  2. Williams, D.B. (2006) J. Cell Sci. 119, 615-623.
  3. Kohno, K. et al. (1993) Mol. Cell. Biol. 13, 877-890.
  4. Ellgaard, L. and Ruddock, L.W. (2005) EMBO Rep. 6, 28-32.
  5. Frand, A.R. and Kaiser, C.A. (1998) Mol. Cell 1, 161-170.
  6. Cabibbo, A. et al. (2000) J. Biol. Chem. 275, 4827-4833.
  7. Kaufman, R.J. et al. (2002) Nat. Rev. Mol. Cell Biol. 3, 411-421.
  8. Nikawa, J. and Yamashita, S. (1992) Mol. Microbiol. 6, 1441-1446.
  9. Cox, J.S. et al. (1993) Cell 73, 1197-1206.
  10. Mori, K. et al. (1993) Cell 74, 743-756.
  11. Lee, K. et al. (2002) Genes Dev. 16, 452-466.
  12. Shen, J. and Prywes, R. (2004) J. Biol. Chem. 279, 43046-43051.
  13. Harding, H.P. et al. (1999) Nature 397, 271-274.
  14. Shi, Y. et al. (1998) Mol. Cell. Biol. 18, 7499-7509.
  15. Zinszner, H. et al. (1998) Genes Dev 12, 982-95.

Background References

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