Caenorhabditis elegans Galectins LEC-6 and LEC-10 Interact with Similar Glycoconjugates in the Intestine

Abstract

Galectins are a family of metazoan proteins that show binding to various β-galactoside-containing glycans. Because of a lack of proper tools, the interaction of galectins with their specific glycan ligands in the cells and tissues are largely unknown. We have investigated the localization of galectin ligands in Caenorhabditis elegans using a novel technology that relies on the high binding specificity between galectins and their endogenous ligands. Fluorescently labeled recombinant galectin fusions are found to bind to ligands located in diverse tissues including the intestine, pharynx, and the rectal valve. Consistent with their role as galactoside-binding proteins, the interaction with their ligands is inhibited by galactose or lactose. Two of the galectins, LEC-6 and LEC-10, recognize ligands that co-localize along the intestinal lumen. The ligands for LEC-6 and LEC-10 are absent in three glycosylation mutants bre-1, fut-8, and galt-1, which have been shown to be required to synthesize the Gal-β1,4-Fuc modifications of the core N-glycans unique to C. elegans and several other invertebrates. Both galectins pull down the same set of glycoproteins in a manner dependent on the presence of these carbohydrate modifications. Endogenous LEC-6 and LEC-10 are expressed in the intestinal cells, but they are localized to different subcellular compartments that do not appear to overlap with each other or with the location of their glycan targets. An altered subcellular distribution of these ligands is found in mutants lacking both galectins. These results suggest a model where LEC-6 and LEC-10 interact with glycoproteins through specific glycans to regulate their cellular fate.

Galectin LEC-6 Interacts with Glycoprotein F57F4.4 to Cooperatively Regulate the Growth of Caenorhabditis elegans

“…15) Our present results are consistent with, and support to their observation; that is, we also found LEC-6 interacts with F57F4.3/4 protein in vitro, and furthermore, presented a evidence that the interaction between these The worms were fed with equal amount of E. coli expressing double-stranded RNA targeted to indicated genes, or mock. Feeding was begun at the L4 stage.…”

Analysis of Protein Turnover by Quantitative SNAP‐Based Pulse‐Chase Imaging

“…However, this strategy is easily adaptable to other proteins (e.g. Figure 3 D) as well, and similar strategies have been used by us and other investigators, in a range of organisms and for different applications (Jansen et al, 2007;Erhardt et al, 2008;McMurray and Thorner, 2008;Maduzia et al, 2010;Bojkowska et al, 2011;Campos et al, 2011;Dunleavy et al, 2011;Silva et al, in press; also reviewed in O' Hare et al, 2007). We will describe two typical types of SNAP-labeling strategies: Pulse-Chase (Basic Protocol 1) and Quench-Chase-Pulse (Basic Protocol 2), which allow for the analysis of old and new protein pools, respectively.…”

The DC2.3 Gene in Caenorhabditis elegans Encodes a Galectin That Recognizes the Galactose.BETA.1.RAR.4Fucose Disaccharide Unit

“…Endogenous glycoproteins that bind to LEC-6 have been reported previously. [20][21][22][23] We recently suggested that F57F4.4 is the major glycoprotein ligand for LEC-6.…”