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Published on: October 9, 2016
Membrane-associated STAT3 and PY-STAT3 in the cytoplasm
Mehul Shah1, Kirit Patel, Somshuvra Mukhopadhyay
1Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595, USA.
STAT3 signaling is not exclusively cytosolic. This study reveals STAT3 associates with early endosomes, impacting interleukin-6 (IL-6) signal transduction and transcriptional activation via the endocytic pathway.
Area of Science:
- Cell Biology
- Molecular Biology
- Signal Transduction
Background:
- Signal transduction by STAT proteins is traditionally viewed as a soluble cytosolic process.
- The role of intracellular trafficking pathways in STAT protein signaling remains incompletely understood.
Purpose of the Study:
- To investigate the association of STAT3 with the endocytic pathway.
- To determine the functional significance of STAT3's interaction with early endosomes in interleukin-6 (IL-6) signaling.
Main Methods:
- Cell fractionation to isolate early endosomes.
- Immunofluorescence and electron microscopy to confirm protein localization.
- Reporter gene assays to assess STAT3 transcriptional activity.
Main Results:
- Constitutive association of STAT3 with early endosomes was observed.
- Interleukin-6 (IL-6) treatment significantly increased the association of phosphorylated STAT3 (pY-STAT3) with early endosomes.
- Modulation of endocytic pathway components affected STAT3-mediated transcriptional activation.
Conclusions:
- The endocytic pathway, specifically early endosomes, plays a crucial role in IL-6/STAT3 signal transduction.
- STAT3 localization to early endosomes is a dynamic and functionally relevant aspect of its signaling mechanism.
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