Decoding the multifaceted roles of galectins in self-defense.

Area of Science:

• Immunology
• Glycobiology
• Cell Biology

Background:

• Galectins are proteins with diverse immune functions, but their roles can seem ambiguous due to varied ligands (glycans).
• Existing reviews may overwhelm newcomers, obscuring the core biological significance of galectins.
• Understanding galectin functions is crucial, especially when host integrity is compromised.

Purpose of the Study:

• To re-evaluate the complex roles of galectins in host defense.
• To clarify galectin functions, particularly when host integrity is compromised.
• To provide a foundational understanding of galectin-glycan interactions and cellular localization.

Main Methods:

• Review of foundational aspects of galectin biology.
• Analysis of galectin glycan binding specificity and carbohydrate-recognition domains.
• Discussion of galectin localization paradox and liquid-liquid phase separation.

Main Results:

• Galectins recognize galactose, an evolutionarily recent monosaccharide.
• The review emphasizes the biological importance of specific carbohydrate-recognition domains.
• Galectin's cytosolic location and function in host defense despite secretory pathway glycan synthesis is discussed.

Conclusions:

• Galectins play multifaceted roles in host defense, particularly under compromised conditions.
• Clarifying galectin-glycan interactions and cellular behavior (e.g., phase separation) is key to understanding their significance.
• This review aims to demystify galectin functions for a clearer understanding of their biological importance in immunity.