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A High Resolution Method to Monitor Phosphorylation-dependent Activation of IRF3
Published on: January 24, 2016
Evidence implicating a mid-region sequence of IGFBP-3 in its specific IGF-independent actions
A D Hollowood1, C E H Stewart, C M Perks
1University Department of Surgery, Bristol Royal Infirmary, Bristol, BS2 8HW, United Kingdom.
Journal of Cellular Biochemistry
|September 5, 2002
Summary
Insulin-like growth factor binding protein-3 (IGFBP-3) can promote cancer cell death. Modifications to specific serine residues in IGFBP-3, like phosphorylation, can block this pro-apoptotic effect, suggesting a regulatory mechanism.
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Research
Background:
- Insulin-like growth factor binding protein-3 (IGFBP-3) regulates insulin-like growth factor bioavailability.
- IGFBP-3 possesses functions independent of growth factor regulation, including effects on cellular homeostasis.
- Previous studies indicated IGFBP-3 can enhance UV-induced apoptosis in carcinoma cells.
Purpose of the Study:
- To investigate the role of the IGFBP-3 mid-region in UV-induced apoptosis.
- To determine if modifications to serine residues Ser(111) and Ser(113) affect IGFBP-3's pro-apoptotic activity.
- To explore phosphorylation as a regulatory mechanism for IGFBP-3's apoptotic function.
Main Methods:
- Utilized the KYSE 190 esophageal carcinoma cell line.
- Synthesized a 15 amino acid peptide from the IGFBP-3 mid-region to mimic intact protein effects.
- Employed two protocols to modify serine residues Ser(111) and Ser(113) via phosphorylation and derivatization.
Main Results:
- A 15 aa peptide from the IGFBP-3 mid-region replicated the pro-apoptotic effect of the full-length protein.
- Phosphorylation and derivatization of serine residues Ser(111) and Ser(113) negated the enhancement of UV-induced cell death.
- Evidence supports the variable mid-region's role in IGFBP-3's specific pro-apoptotic functions.
Conclusions:
- The variable mid-region of IGFBP-3 is crucial for its pro-apoptotic activity.
- Phosphorylation of IGFBP-3 may serve as a regulatory mechanism to control its pro-apoptotic function.
- Targeting IGFBP-3 modifications could offer therapeutic strategies for esophageal carcinoma.
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