[Frontiers in Bioscience S4, 864-887, January 1, 2012]

Integrating structure and function of 'tandem-repeat' galectins

Maria F. Troncoso1, Maria T. Elola1, Diego O. Croci2, Gabriel A. Rabinovich2,3

1Institute of Biological Chemistry and Physicochemistry (UBA-CONICET), Department of Biological Chemistry, School of Pharmacy and Biochemistry, University of Buenos Aires, 2Laboratory of Immunopathology, Institute of Biology and Experimental Medicine (IBYME-CONICET), 3Department of Biological Chemistry, School of Exact and Natural Sciences, University of Buenos Aires, Buenos Aires, Argentina

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Galectin-4
3.1. Galectin-4 in inflammation
3.1.1. Galectin-4 in intestinal inflammation
3.2. Galectin-4 in cancer
4. Galectin-6
5. Galectin-8
5.1. Galectin-8 in inflammation
5.1.1. Galectin-8 in autoimmune inflammation
5.1.2. Galectin-8 in the control of T-cell function and homeostasis
5.1.3. Galectin-8 and neutrophils: key mediators of acute inflammation
5.2. Galectin-8 in cancer
6. Galectin-9
6.1. Galectin-9 in inflammation
6.1.1. Galectin-9 in allergic inflammation
6.1.2. Galectin-9 in autoimmunity and other chronic inflammatory disorders
6.1.3. Galectin-9 in infection-associated inflammation
6.2. Galectin-9 in cancer
7. Galectin-12
7.1. Galectin-12 in cancer
8. Summary and Perspective
9. Acknowledgements
10. References

1. ABSTRACT

Galectins (GALs) are evolutionarily-conserved lectins defined by at least one carbohydrate recognition domain (CRD) with affinity for beta-galactosides and conserved sequence motifs. Although the biological roles of some members of this family, including the 'proto-type' GAL-1 and the 'chimera-type' GAL-3 have been widely studied, the functions of 'tandem-repeat' galectins are just emerging. The subgroup of 'tandem-repeat' galectins (GAL-4, -6, -8, -9, and -12) contain two distinct CRDs, connected by a linker peptide. Here we integrated and distilled the available information on 'tandem-repeat' galectins, their specific structures, potential ligands and biological activities in inflammatory and neoplastic diseases. While GAL-4 has been implicated in inflammatory bowel diseases, either as a pro-inflammatory or pro-apoptotic mediator, GAL-8 plays roles in autoimmune diseases such as rheumatoid arthritis and lupus erythematosus and modulates tumor progression. GAL-9 controls allergic inflammation and Th1/Th17-mediated autoimmunity and has prognostic value in certain tumor types. Finally, GAL-12 plays important roles in adipocyte physiology. Although this information is just emerging, further studies are needed to dissect the biological roles of 'tandem-repeat' galectins in health and disease.