ERp57

Protein Overview

ERp57, also known as PDIA3, is a thiol-disulfide oxidoreductase of the protein disulfide isomerase family. In the endoplasmic reticulum, it works with the calnexin and calreticulin chaperone system to promote folding, disulfide-bond formation, and quality control of newly synthesized glycoproteins. ERp57 can also participate in antigen processing, cellular stress responses, and redox regulation.

Expected Localization

Predominantly the endoplasmic reticulum, producing a reticular cytoplasmic pattern that surrounds the nucleus and extends through the cytoplasm.

Depending on cell type and condition, additional nuclear, cell-surface, or extracellular pools have been reported.

Expected Expression Pattern

Broadly expressed across mammalian tissues and cell lines, with higher abundance often observed in cells with substantial secretory or protein-folding activity. Expression may increase during endoplasmic reticulum stress or activation of the unfolded protein response.

Relevant Pathways

Protein folding and disulfide-bond formation
Calnexin/calreticulin chaperone cycle
Endoplasmic reticulum quality control
Unfolded protein response and ER stress
MHC class I antigen processing

HeLa cells were cultured in a 12-well format Cytos slide kit overnight then fixed with 4% formaldehyde for 30 minutes, permeabilized using 70% ethanol for 10 minutes. The slide kit was then assembled into a flow cell and loaded onto an AVITI24™ along with the Cytos Protein Cartridge for a multiomics cell screening run. ERp57 demonstrated strong endoplasmic reticulum localization and high signal-to-noise ratio, with no detectable probe crosstalk. These results support high confidence in target-specific detection and validate this antibody as a passing clone. A549 cells were also cultured and processed under the same protocol in parallel as part of Cytos cross-run reproducibility testing.

Signal-to-noise ratio
Acceptance criteria: > 2x background

Pass

14.5 ± 4.2 (HeLa; n=26 runs)
8.1 ± 1.4 (A549; n=34 runs)

Indicates the fold brightness of the target signal as measured by the Mean Intensity Above (Otsu-defined) Threshold (IAT), over the background (a channel-matched isotype control) in the same cell. Data shown are mean ± standard deviation across independent reproducibility runs. The ratio ranges from 8–14 across HeLa and A549 cells, indicating that the signal is 4–7 times above the acceptance threshold — a clean, easily distinguishable signal.

Panel-level run-to-run reproducibility
Acceptance criteria: R² > 0.9

Pass

For each imaging panel, we assess reproducibility by comparing the intensity signal a given antibody target produces across independent replicate runs. Within each run, we measure the average per-well fluorescence intensity for every target in the panel. We then plot each target's intensity from one run against the matching target's intensity from another run of the same layout, and calculate the Pearson correlation coefficient (r) between those two sets of measurements. Squaring that value gives the R² (coefficient of determination), which reports what fraction of the variation in one run's signal is explained by the other run's signal.

Protein Overview

Clone Information

Qualitative Results

Quantitative Results

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