Galectins are an evolutionarily conserved family of glycan-binding proteins with multifunctional roles in immunity. These proteins often shuttle between different intracellular compartments (nucleus, cytoplasm, and organelles) and are released to the extracellular milieu, where they acquire different roles in response to diverse microenvironmental stimuli, including hypoxia, nutrient availability, intracellular and extracellular pH, cytokine milieu and the presence of proinflammatory or immunosuppressive signals. Within the immune system, galectins can elicit a wide array of important functions that tailor both innate and adaptive responses, playing key roles in shaping the choreography of immune cells in health and disease. Interestingly, the same galectin can function as a cytokine, chemokine, cell adhesion molecule, immune checkpoint molecule, danger-associated molecular pattern, or growth factor depending on different cellular programs, including activation, differentiation, and trafficking, or during pathologic conditions, such as pathogen invasion, autoimmune inflammation, fibrosis and cancer.
Learn more from the great white paper by Gabriel Rabinovich!

The multifaceted roles of galectins: glycan-binding proteins with multiple personalities (glycoforum.gr.jp)