NPM1

Protein Overview

NPM1 (nucleophosmin/B23) is a multifunctional nucleolar chaperone that regulates rRNA transcription/processing and pre-ribosomal particle assembly and export, participates in centrosome duplication and genomic stability, and modulates the p53/ARF tumor suppressor axis. It also chaperones histones during nucleosome assembly and shuttles continuously between nucleolus, nucleoplasm, and cytoplasm. NPM1 is a generic nucleolar/proliferation marker rather than a neuro-specific protein; it is included in this Neuro Morphology panel as a general nuclear reference target validated in HeLa cells, alongside the panel's neuro-specific markers (GFAP, MAP2, βIII-Tubulin).

Expected Localization

Predominantly nucleolar, with dynamic shuttling through the nucleoplasm and transient cytoplasmic transit; also localizes to centrosomes during mitosis.

Normal immunofluorescence shows a punctate/granular nucleolar staining pattern with little diffuse cytoplasmic signal.

Expected Expression Pattern

Ubiquitously expressed in essentially all proliferating and non-proliferating human tissues, with higher levels in cells with high proliferative/ribosome biogenesis demand (e.g., hematopoietic progenitors, epithelial crypts, tumor cells). Subcellular distribution (nucleolar vs. cytoplasmic) is the more biologically informative variable than absolute level.

Relevant Pathways

Ribosome biogenesis / rRNA processing and pre-ribosomal export
p53-ARF tumor suppressor signaling
Centrosome duplication and genomic stability maintenance
Histone chaperoning and nucleosome assembly
Nucleolar stress signaling

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. NPM1 demonstrated strong nucleoli and nucleoplasm 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. SH-SY5Y and 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

3.4 ± 0.6 (SH-SY5Y; n=3 runs)
3.6 ± 0.8 (HeLa; n=17 runs)
7.8 ± 1.3 (A549; n=15 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 3.4–7.8 across SH-SY5Y, HeLa, and A549 cells, consistently over 2 times 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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