Galectin-3 interactions with glycosphingolipids.Collins, P.M., Bum-Erdene, K., Yu, X., Blanchard, H.
(2014) J.Mol.Biol. 426: 1439-1451
- PubMed: 24326249
- DOI: 10.1016/j.jmb.2013.12.004
- Primary Citation of Related Structures:
- PubMed Abstract:
Galectins have essential roles in pathological states including cancer, inflammation, angiogenesis and microbial infections. Endogenous receptors include members of the lacto- and neolacto-series glycosphingolipids present on mammalian cells and cont ...
Galectins have essential roles in pathological states including cancer, inflammation, angiogenesis and microbial infections. Endogenous receptors include members of the lacto- and neolacto-series glycosphingolipids present on mammalian cells and contain the tetrasaccharides lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT) that form their core structural components and also ganglio-series glycosphingolipids. We present crystallographic structures of the carbohydrate recognition domain of human galectin-3, both wild type and a mutant (K176L) that influenced ligand affinity, in complex with LNT, LNnT and acetamido ganglioside a-GM3 (α2,3-sialyllactose). Key structural features revealed include galectin-3's demonstration of a binding mode towards gangliosides distinct from that to the lacto/neolacto-glycosphingolipids, with its capacity for recognising the core β-galactoside region being challenged when the core oligosaccharide epitope of ganglio-series glycosphingolipids (GM3) is embedded within particular higher-molecular-weight glycans. The lacto- and neolacto- glycosphingolipids revealed different orientations of their terminal galactose in the galectin-3-bound LNT and LNnT structures that has significant ramifications for the capacity of galectin-3 to interact with higher-order lacto/neolacto-series glycosphingolipids such as ABH blood group antigens and the HNK-1 antigen that is common on leukocytes. LNnT also presents an important model for poly-N-acetyllactosamine-containing glycans and provides insight into galectin-3's accommodation of extended oligosaccharides such as the poly-N-acetyllactosamine-modified N- and O-glycans that, via galectin-3 interaction, facilitate progression of lung and bladder cancers, respectively. These findings provide the first atomic detail of galectin-3's interactions with the core structures of mammalian glycosphingolipids, providing information important in understanding the capacity of galectin-3 to engage with receptors identified as facilitators of major disease.
Institute for Glycomics, Griffith University Gold Coast Campus, Queensland 4222, Australia.,Institute for Glycomics, Griffith University Gold Coast Campus, Queensland 4222, Australia. Electronic address: firstname.lastname@example.org.