Product: Phospho-eIF2 alpha (Ser51)[Ser52] Antibody
Catalog: AF3087
Description: Rabbit polyclonal antibody to Phospho-eIF2 alpha (Ser51)[Ser52]
Application: WB IHC IF/ICC
Reactivity: Human, Mouse, Rat
Prediction: Pig, Bovine, Horse, Sheep, Rabbit, Dog, Chicken, Xenopus
Mol.Wt.: 38kDa; 36kD(Calculated).
Uniprot: P05198
RRID: AB_2834524

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 100ul $280 In stock
 200ul $350 In stock

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Product Info

WB 1:500-1:2000, IHC 1:50-1:500, IF/ICC 1:100-1:500
*The optimal dilutions should be determined by the end user.

WB: For western blot detection of denatured protein samples. IHC: For immunohistochemical detection of paraffin sections (IHC-p) or frozen sections (IHC-f) of tissue samples. IF/ICC: For immunofluorescence detection of cell samples. ELISA(peptide): For ELISA detection of antigenic peptide.

Pig(100%), Bovine(100%), Horse(100%), Sheep(100%), Rabbit(100%), Dog(100%), Chicken(100%), Xenopus(100%)
Phospho-eIF2 alpha (Ser51) Antibody detects endogenous levels of eIF2 alpha only when phosphorylated at Ser52, which site historically referenced as Ser51.
Cite Format: Affinity Biosciences Cat# AF3087, RRID:AB_2834524.
The antibody is from purified rabbit serum by affinity purification via sequential chromatography on phospho-peptide and non-phospho-peptide affinity columns.
Rabbit IgG in phosphate buffered saline , pH 7.4, 150mM NaCl, 0.02% sodium azide and 50% glycerol. Store at -20 °C. Stable for 12 months from date of receipt.


EIF 2 alpha; EIF 2; EIF 2A; EIF 2alpha; eIF-2-alpha; eIF-2A; EIF-2alpha; EIF2 alpha; EIF2; EIF2A; EIF2S1; Eukaryotic translation initiation factor 2 subunit 1 alpha 35kDa; Eukaryotic translation initiation factor 2 subunit 1 alpha; Eukaryotic translation initiation factor 2 subunit 1; Eukaryotic translation initiation factor 2 subunit alpha; IF2A_HUMAN;


eIF2A a translation initiation factor that functions in the early steps of protein synthesis by forming a ternary complex with GTP and initiator tRNA. This complex binds to a 40s ribosomal subunit, followed by mRNA binding to form a 43S preinitiation complex.



Score>80(red) has high confidence and is suggested to be used for WB detection. *The prediction model is mainly based on the alignment of immunogen sequences, the results are for reference only, not as the basis of quality assurance.

Model Confidence:
High(score>80) Medium(80>score>50) Low(score<50) No confidence

PTMs - P05198 As Substrate

Site PTM Type Enzyme
S5 Phosphorylation
K12 Ubiquitination
S26 Phosphorylation
S49 Phosphorylation Q9NZJ5 (EIF2AK3) , Q9BQI3 (EIF2AK1) , P19525 (EIF2AK2) , Q75MR0 (HRI)
S52 Phosphorylation B4DS64 (PRKRIR) , P51812 (RPS6KA3) , P19525 (EIF2AK2) , P28482 (MAPK1) , Q75MR0 (HRI) , Q9BQI3 (EIF2AK1) , Q9NZJ5 (EIF2AK3) , Q05655 (PRKCD) , Q16539 (MAPK14) , Q9P2K8 (EIF2AK4)
S58 Phosphorylation
K61 Ubiquitination
K80 Ubiquitination
Y82 Phosphorylation
S86 Phosphorylation
K87 Ubiquitination
S91 Phosphorylation
K97 Ubiquitination
K101 Acetylation
K101 Ubiquitination
K104 Ubiquitination
K106 Ubiquitination
S110 Phosphorylation
K123 Ubiquitination
R133 Methylation
K141 Acetylation
K141 Ubiquitination
K143 Acetylation
K143 Ubiquitination
Y147 Phosphorylation
Y150 Phosphorylation
K154 Methylation
K154 Ubiquitination
S158 Phosphorylation
T185 Phosphorylation
K190 Ubiquitination
Y200 Phosphorylation
Y202 Phosphorylation
K209 Ubiquitination
S219 Phosphorylation
K226 Ubiquitination
Y235 Phosphorylation
T245 Phosphorylation
K259 Ubiquitination
K265 Ubiquitination
R266 Methylation
K276 Ubiquitination
T279 Phosphorylation
T281 Phosphorylation
T284 Phosphorylation
K312 Ubiquitination

Research Backgrounds


Functions in the early steps of protein synthesis by forming a ternary complex with GTP and initiator tRNA. This complex binds to a 40S ribosomal subunit, followed by mRNA binding to form a 43S pre-initiation complex. Junction of the 60S ribosomal subunit to form the 80S initiation complex is preceded by hydrolysis of the GTP bound to eIF-2 and release of an eIF-2-GDP binary complex. In order for eIF-2 to recycle and catalyze another round of initiation, the GDP bound to eIF-2 must exchange with GTP by way of a reaction catalyzed by eIF-2B.


Substrate for at least 4 kinases: EIF2AK1/HRI, EIF2AK2/PKR, EIF2AK3/PERK and EIF2AK4/GCN2. Phosphorylation stabilizes the eIF-2/GDP/eIF-2B complex and prevents GDP/GTP exchange reaction, thus impairing the recycling of eIF-2 between successive rounds of initiation and leading to global inhibition of translation. Phosphorylated; phosphorylation on Ser-52 by the EIF2AK4/GCN2 protein kinase occurs in response to amino acid starvation and UV irradiation (By similarity).

Subcellular Location:

Cytoplasm>Stress granule.
Note: Colocalizes with NANOS3 in the stress granules.

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionSubcellular location
Subunit Structure:

Heterotrimer composed of an alpha, a beta and a gamma chain. Component of an EIF2 complex at least composed of CELF1/CUGBP1, CALR, CALR3, EIF2S1, EIF2S2, HSP90B1 and HSPA5. Interaction with METAP2 protects EIF2S1 from inhibitory phosphorylation (By similarity). Interacts with ABCF1 isoform 2. Associates with ribosomes. Interacts with DDX3X in an RNA-independent manner.


Belongs to the eIF-2-alpha family.

Research Fields

· Cellular Processes > Transport and catabolism > Autophagy - animal.   (View pathway)

· Cellular Processes > Cell growth and death > Apoptosis.   (View pathway)

· Genetic Information Processing > Translation > RNA transport.

· Genetic Information Processing > Folding, sorting and degradation > Protein processing in endoplasmic reticulum.   (View pathway)

· Human Diseases > Endocrine and metabolic diseases > Non-alcoholic fatty liver disease (NAFLD).

· Human Diseases > Infectious diseases: Viral > Hepatitis C.

· Human Diseases > Infectious diseases: Viral > Measles.

· Human Diseases > Infectious diseases: Viral > Influenza A.

· Human Diseases > Infectious diseases: Viral > Herpes simplex infection.


1). Upregulation of BCL-2 by acridone derivative through gene promoter i-motif for alleviating liver damage of NAFLD/NASH. NUCLEIC ACIDS RESEARCH (PubMed: 32710621) [IF=14.9]

Application: WB    Species: mouse    Sample: liver

Figure 7. Effect of A22 on ameliorating apoptosis, ER stress, inflammation, metabolic syndrome, and fibrogenesis in HF diet-fed mice. (A) Effect of A22 on BCL-2 gene transcription. (B) Effect of A22 on BAX gene transcription. (C) Effect of A22 on expressions of apoptosis-related proteins in liver. The extracted proteins from the liver were immunoblotted with specific antibodies, and quantified based on the loading control of ACTIN. (D) Effect of A22 on ER stress. The UPR proteins (IRE-1, PERK, elF-2 and CHOP) were analyzed by using western Blot. (E) Effect of A22 on expressions of inflammatory factors. (F) Effect of A22 on expressions of fibrogenic proteins.

2). A marine-derived small molecule induces immunogenic cell death against triple-negative breast cancer through ER stress-CHOP pathway. International Journal of Biological Sciences (PubMed: 35541893) [IF=9.2]

Application: WB    Species: human    Sample: MDA-MB-231 cells

Figure 2. | MHO7 induced ER stress and cell cycle arrest in TNBC cells.(D) The expression of BiP/p-PERK/p-eIF2α/ATF4/CHOP were measured by western blot under MHO7 treatment in MDA-MB-231 cells.

3). Betulinic acid chemosensitizes breast cancer by triggering ER stress-mediated apoptosis by directly targeting GRP78. Cell Death & Disease (PubMed: 29802332) [IF=9.0]

Application: WB    Species: human    Sample: MCF-7,MDA-MB-231

Fig. 5 BA triggers breast cancer cells apoptosis via ER stress-mediated pathway. a MCF-7 and MDA-MB-231 cells were treated with the indicated concentrations of BA for 24 h, and the protein levels of ER stress-associated signals were stimulated by BA in a dose-dependent manner, including GRP78, p-PERK/PERK, p-eIF2α/eIF2α, CHOP, and caspase-12. b MCF-7 and MDA-MB-231 cells were treated with BA alone or in combination with taxol for 24 h, the expression levels of GRP78, p-PERK/PERK, p-eIF2α/eIF2α, CHOP, and caspase-12 were also significantly upregulated following drug administration, especially in the co-treatment group, indicating the ER stress-mediated apoptosis pathway was aggravatedly activated by drug combination.

4). Modulating endoplasmic reticulum stress in APP/PS1 mice by Gomisin B and Osthole in Bushen-Yizhi formula: Synergistic effects and therapeutic implications for Alzheimer's disease. Phytomedicine (PubMed: 37586159) [IF=7.9]

5). Up-regulation of thioredoxin system by puerarin inhibits lipid uptake in macrophages. Free radical biology & medicine (PubMed: 33242606) [IF=7.4]

6). Microcystin-leucine arginine induced the apoptosis of GnRH neurons by activating the endoplasmic reticulum stress resulting in a decrease of serum testosterone level in mice. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY (PubMed: 33396074) [IF=6.8]

Application: WB    Species: Mice    Sample: GT1–7 cells

Fig. 4. Activation of the endoplasmic reticulum stress (ERs) in GnRH neurons and GT1–7 cells after MC-LR treatment. (A) MC-LR triggered ultrastructural changes of ERs in hypothalamus neurons. Drinking water including 15 μg/L MCLR was fed to mice for 180 days without interruption, and the ultrastructure of ERs (black arrows) in control and MC-LR treatment group were detected by electron microscope. (B) Increase of intracellular Ca2+ concentration in GT1–7 cells following exposure to MC-LR. Fluo-3/AM fluorescent probes were used to measure levels of intracellular Ca2+ through immunofluorescence assay (scale bar = 100 µm). (C) The intensity of Fluo-3/AM was detected by image-pro plus (n = 3). (D) Mice were given drinking water comprising MC-LR for 180 sustained days. Expressions of GRP78, ATF6, ATF4, PERK, CHOP, eIF2α, peIF2α, and LC3B in hypothalamus tissues were assessed by Western blotting (n = 5 mice/ group). (E) GT1–7 cells were plated in 6-well plates at 2.0 × 105 cells per well. Cells were exposed to MC-LR for 24 h at different doses as indicated. Expressions of GRP78, ATF6, ATF4, PERK, CHOP, eIF2α, p- eIF2α, and LC3B in GT1–7 cells were assessed by Western blotting. (F) GT1–7 cells were plated in 6-well plates at 2.0 × 105 cells per well. Cells were pretreated with ERs inhibitor 4- Phenyl butyric acid (4- PBA) at 5 mM for 1 h, followed by the treatment with MC-LR (1000 nM) for 24 h. The expression levels of ERs related proteins and LC3B were measured.

7). Icariin improves the cognitive function of APP/PS1 mice via suppressing endoplasmic reticulum stress. LIFE SCIENCES (PubMed: 31400352) [IF=6.1]

Application: WB    Species: mouse    Sample: hippocampus

Fig.6 |Effects of ICA on the PERK signaling in the hippocampus of APP/PS1 mice. The phosphorylation of PERK and eIF2α, as well ATF4 and CHOP proteins expression were increased in APP/PS1 mice, ICA treatment significantly decreased their levels. (A, B) Immunoblots of PERK, p-PERK, eIF2α, p-eIF2α, ATF4 and CHOP.

8). Protective Effect of Patchouli Alcohol Against High-Fat Diet Induced Hepatic Steatosis by Alleviating Endoplasmic Reticulum Stress and Regulating VLDL Metabolism in Rats. Frontiers in Pharmacology (PubMed: 31632274) [IF=5.6]

Application: WB    Species: rat    Sample: liver

FIGURE 5 | PA treatment attenuated HFD-induced VLDLR expression in rats. (A) Representative immunoreactive bands of eIF2α, p-eIF2α, ATF4, and VLDLR

9). CTRP1 attenuates cerebral ischemia/reperfusion injury via the PERK signaling pathway. Frontiers in Cell and Developmental Biology (PubMed: 34422821) [IF=5.5]

Application: WB    Species: Rat    Sample: cortex

FIGURE 5 CTRP1 inhibited ERS via PERK signal pathway in the cortex of MCAO/R-treated rats. (A) Western blot analyzed the expression of PERK, p-PERK, GRP78, ATF6, ATF4, IRE1α, p-IRE1α. n = 4 per group. (B) CTRP1 affected the interaction between PERK and GRP78 after CIRI. n = 3 per group. ****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05 vs. sham group, ####p < 0.0001, ###p < 0.001, ## p < 0.01, #p < 0.05 vs. MCAO/R + LV-NC group.

10). ATP citrate lyase inhibitor triggers endoplasmic reticulum stress to induce hepatocellular carcinoma cell apoptosis via p‐eIF2α/ATF4/CHOP axis. JOURNAL OF CELLULAR AND MOLECULAR MEDICINE (PubMed: 33393219) [IF=5.3]

Application: WB    Species: Human    Sample: HepG2 cells

FIGURE 5 ACLY inhibitor triggers ER stress and activates p‐eIF2α/ATF4/CHOP axis in vitro. Western blot analysis of (A) ER stress‐related proteins (p‐eIF2α, eIF2α, ATF4 and CHOP) and (B) UPR signal transduction molecules (p‐PERK, PERK, p‐IRE1α, IRE1α and sXBP1) in HepG2 cells after administration of BMS‐303141. ATF4p‐eIF2α, eIF2α were activated 3 h post‐treatment; CHOP was activated 8 h post‐treatment. (* P < .05, ** P < .01 and *** P < .001, compared with control group) (C) Western blot analysis of protein expression after ATF4 knockdown. (D) Annexin V‐FITC/PI double staining was performed to determine the apoptosis rate of HepG2 cells after ATF4 knockdown via flow cytometry. (* P < .05, ** P < .01 and *** P < .001, compared with con siRNA group). All experiments were repeated 3 times

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