Cell Signaling Technology

Product Pathways - PathScan ELISA

PathScan® Phospho-eIF2α (Ser51) Sandwich ELISA Kit #7286

When ordering five or more kits, please contact us for processing time and pricing at sales@cellsignal.com.

Kit Includes Volume Solution Color
eIF2alpha Rabbit antibody Coated Microwells 96 tests
Phospho-eIF2alpha (Ser51) Mouse Detection Antibody 11 ml Green
Anti-mouse IgG, HRP-linked Antibody 11 ml Red
TMB Substrate #7004 11 ml Colorless
STOP Solution #7002 11 ml Colorless
Sealing Tape 2 sheets
ELISA Wash Buffer (20X) 25 ml Colorless
ELISA Sample Diluent 25 ml Blue
Cell Lysis Buffer (10X) #9803 15 ml Yellowish

Note: 12 8-well modules –Each module is designed to break apart for 8 tests.
Note: Kit should be stored at 4°C with the exception of Cell Lysis Buffer, which is stored at –20°C (packaged separately).

Species Cross-Reactivity

H M

Reactivity Key:  H=Human  M=Mouse
Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Description

The PathScan® Phospho-eIF2α (Ser51) Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of eIF2α phosphorylated at Ser51. A eIF2α rabbit antibody has been coated onto the microwells. After incubation with cell lysates, eIF2α protein is captured by the coated antibody. Following extensive washing, a phospho-eIF2α (Ser51) mouse detection antibody is added to detect captured phospho-eIF2α protein. Anti-mouse IgG, HRP-linked antibody is then used to recognize the bound mouse detection antibody. HRP substrate TMB is added to develop color. The magnitude of the absorbance for this developed color is proportional to the quantity of eIF2α phosphorylated at Ser51.Antibodies in kit are custom formulations specific to kit.

Specificity / Sensitivity

The PathScan® Phospho-eIF2α (Ser51) Sandwich ELISA Kit #7286 detects endogenous levels of eIF2α protein when phosphorylated at Ser51 as shown in Figure 1. Kit sensitivity is shown in Figure 2. This kit detects proteins from the indicated species, as determined through in-house testing, but may also detect homologous proteins from other species.

ELISA

ELISA

Figure 2. The relationship between the protein concentration of lysates from Jurkat cells, treated with Calyculin A #9902 and pervanadate or LY294002, and the absorbance at 450 nm using PathScan® Phospho-eIF2α (Ser51) Sandwich ELISA Kit is shown.

ELISA - Western correlation

ELISA - Western correlation

Figure 1. Treatment of Jurkat cells with 100 nM Calyculin A #9902 and 1 mM pervanadate increases phosphorylation of eIF2α at Ser51, detected by the PathScan® Phospho-eIF2α (Ser51) Sandwich ELISA Kit #7286, but does not affect the levels of total eIF2α detected by PathScan® Total eIF2α Sandwich ELISA Kit #7952. The absorbance readings at 450 nm are shown in the top figure, while the corresponding western blots using eIF2α (L57A5) Mouse mAb #2103 (left panel) or Phospho-eIF2α (Ser51) (119A11) Rabbit mAb #3597 (right panel) are shown in the bottom figure.

Background

Phosphorylation of the eukaryotic initiation factor 2 (eIF2) α subunit is a well-documented mechanism to downregulate protein synthesis under a variety of stress conditions. eIF2 binds GTP and Met-tRNAi and transfers Met-tRNA to the 40S subunit to form the 43S preinitiation complex (1,2). eIF2 promotes a new round of translation initiation by exchanging GDP for GTP, a reaction catalyzed by eIF2B (1,2). Kinases that are activated by viral infection (PKR), endoplasmic reticulum stress (PERK/PEK), amino acid deprivation (GCN2), or heme deficiency (HRI) can phosphorylate the α subunit of eIF2 (3,4). This phosphorylation stabilizes the eIF2-GDP-eIF2B complex and inhibits the turnover of eIF2B. Induction of PKR by IFN-γ and TNF-α induces potent phosphorylation of eIF2α at Ser51 (5,6).

  1. Kimball, S.R. (1999) Int. J. Biochem. Cell Biol. 31, 25-29.
  2. De Haro, C. et al. (1996) FASEB J. 10, 1378-1387.
  3. Kaufman, R.J. (1999) Genes Dev. 13, 1211-1233.
  4. Sheikh, M.S. and Fornace Jr., A.J. (1999) Oncogene 18, 6121-6128.
  5. Cheshire, J.L. et al. (1999) J. Biol. Chem. 274, 4801-4806.
  6. Zamanian-Daryoush, M. et al. (2000) Mol. Cell. Biol. 20, 1278-1290.

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