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Updated: Aug 13, 2026
Time-resolved Förster Resonance Energy Transfer Assays for Measurement of Endogenous Phosphorylated STAT Proteins in Human Cells
Published on: September 9, 2021
Systemic evaluation of total Stat3 and Stat3 tyrosine phosphorylation in normal human tissues
Chun-Liang Chen1, Fu-Chuan Hsieh, Jiayuh Lin
1Center for Childhood Cancer, Columbus Children's Research Institute, Columbus, OH 43205, USA.
Abstract:
Stat3 plays important roles in many biological phenomena including cell survival, growth, proliferation, differentiation and cancer malignancies. As Stat3 emerges as a new therapeutic target for treatment of cancers in which the Stat3 is constitutively activated, the overall evaluation of basal expression of Stat3 and phosphorylated Stat3 at tyrosine residue 705 in human tissues would be very important and informative. We took a pilot study to examine the expression patterns of total Stat3 and phosphorylated Stat3 protein (p-Stat3) using immunohistochemistry in 47 different adult normal human tissues of 10 organ systems. Immunohistochemistry showed that total Stat3 protein was almost universally detected in all tissues except peripheral nerve. Interestingly, majorities of tissues showed to have moderate to high expression levels of total Stat3 protein. Several heart tissues displayed a unique perinuclear immunostaining for both Stat3 and p-Stat3, most likely in Golgi complexes. Based on the cell types, the p-Stat3 was also expressed in glandular, secretory, mucosal epithelial, circulatory endothelial, lymphoid, proliferative, and reabsorption-active cells.
Insights
Signal transducer and activator of transcription 3 (Stat3) is widely expressed in normal human tissues, with high levels in most. Phosphorylated Stat3 (p-Stat3) is also found in various cell types, indicating its broad biological roles.
Area of Science:
- Molecular Biology
- Cell Biology
- Oncology
Background:
- Signal transducer and activator of transcription 3 (Stat3) is crucial for cell survival, growth, proliferation, differentiation, and cancer development.
- Constitutive activation of Stat3 in cancers positions it as a significant therapeutic target.
- Understanding basal Stat3 expression in normal tissues is vital for evaluating its role in cancer and potential side effects of targeted therapies.
Purpose of the Study:
- To investigate the expression patterns of total Stat3 and phosphorylated Stat3 (p-Stat3) in a wide range of normal adult human tissues.
- To provide a comprehensive overview of Stat3 and p-Stat3 expression across different organ systems.
Main Methods:
- Immunohistochemistry was employed to detect total Stat3 and p-Stat3 protein.
- The study analyzed 47 different adult normal human tissues from 10 organ systems.
Main Results:
- Total Stat3 protein was ubiquitously detected in nearly all examined tissues, with moderate to high expression levels in the majority.
- Peripheral nerve tissue was the only exception, showing no detectable total Stat3.
- Phosphorylated Stat3 (p-Stat3) was found in various cell types, including glandular, secretory, mucosal epithelial, circulatory endothelial, lymphoid, proliferative, and reabsorption-active cells. Unique perinuclear staining for both Stat3 and p-Stat3 was observed in some heart tissues, potentially localized to Golgi complexes.
Conclusions:
- Stat3 is broadly expressed in normal human tissues, suggesting fundamental roles beyond cancer.
- The presence of p-Stat3 in diverse cell types indicates its involvement in various physiological processes.
- This expression profile provides a baseline for understanding Stat3's role in normal physiology and its dysregulation in cancer.
