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An antibody to p16INK4A recognizes a modified form of galectin-3
1Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405, USA.
Abstract:
Galectin-3 is a carbohydrate binding protein involved in multiple processes including cell-cycle regulation and apoptosis. The ability of galectin-3 to protect cells from apoptosis is dependent upon a region of the protein known as a BH-1 domain for its homology to the anti-apoptotic protein Bcl-2. Here, we show that a monoclonal antibody (MAb) to the human tumor suppressor protein p16INK4A recognizes a post-translationally modified form of human galectin-3. The modified form is detectable in only a subset of cell types expressing galectin-3, indicating that the modification is cell-type-specific. Although there is little amino acid sequence homology between p16INK4a and galectin-3, we show by epitope mapping that the modification directly affects the structure of galectin-3's BH-1 domain. Elucidation of the nature of this modification might provide further insight into galectin-3 function.
Insights
A novel post-translational modification of galectin-3, recognized by an antibody to p16INK4A, specifically impacts its cell-protective BH-1 domain. This cell-type-specific modification offers new insights into galectin-3
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Research
Background:
- Galectin-3 is a key carbohydrate-binding protein regulating cell processes like apoptosis and cell-cycle control.
- Its anti-apoptotic function is linked to the BH-1 domain, homologous to Bcl-2.
- Understanding galectin-3's regulation is crucial for cancer research.
Purpose of the Study:
- To investigate a novel post-translational modification of human galectin-3.
- To determine if this modification affects galectin-3's functional domains, particularly the BH-1 domain.
- To explore the cell-type specificity of this galectin-3 modification.
Main Methods:
- Utilized a monoclonal antibody (MAb) targeting the human tumor suppressor protein p16INK4A.
- Performed epitope mapping to identify the modified site on galectin-3.
- Analyzed the expression of the modified galectin-3 in various cell types.
Main Results:
- A p16INK4A-specific MAb recognized a post-translationally modified form of galectin-3.
- This modified galectin-3 was detected in a subset of cell types, indicating cell-type-specific modification.
- Epitope mapping confirmed the modification directly alters the structure of galectin-3's BH-1 domain.
Conclusions:
- A novel, cell-type-specific post-translational modification of galectin-3 exists, affecting its BH-1 domain.
- This modification is recognized by an antibody typically targeting p16INK4A, despite low sequence homology.
- Further elucidation of this modification's nature may reveal new insights into galectin-3's role in apoptosis and disease.