Identification of the Plasticity-Relevant Fucose-α(1−2)-Galactose Proteome from the Mouse Olfactory Bulb

Abstract

Fucose-α(1−2)-galactose [Fucα(1−2)Gal] sugars have been implicated in the molecular mechanisms that underlie neuronal development, learning, and memory. However, an understanding of their precise roles has been hampered by a lack of information regarding Fucα(1−2)Gal glycoproteins. Here, we report the first proteomic studies of this plasticity-relevant epitope. We identify five classes of putative Fucα(1−2)Gal glycoproteins: cell adhesion molecules, ion channels and solute carriers/transporters, ATP-binding proteins, synaptic vesicle-associated proteins, and mitochondrial proteins. In addition, we show that Fucα(1−2)Gal glycoproteins are enriched in the developing mouse olfactory bulb (OB) and exhibit a distinct spatiotemporal expression that is consistent with the presence of a “glycocode” to help direct olfactory sensory neuron (OSN) axonal pathfinding. We find that expression of Fucα(1−2)Gal sugars in the OB is regulated by the α(1−2)fucosyltransferase FUT1. FUT1-deficient mice exhibit developmental defects, including fewer and smaller glomeruli and a thinner olfactory nerve layer, suggesting that fucosylation contributes to OB development. Our findings significantly expand the number of Fucα(1−2)Gal glycoproteins and provide new insights into the molecular mechanisms by which fucosyl sugars contribute to neuronal processes.

Molecular Clock Regulates Daily α1–2-Fucosylation of the Neural Cell Adhesion Molecule (NCAM) within Mouse Secondary Olfactory Neurons

“…The inhibition of ␣1-2-fucosylation caused by 2-deoxy-D-galactose incorporation delays neurite outgrowth and synaptic plasticity in the rat hippocampus (29,30). Mice that are deficient in FUT1 exhibit developmental defects in neurons that express NCAM in the OB (25). We showed that the abundance of ␣1-2Fuc glycan fluctuates in the lateral olfactory tract, which mostly contains axons of secondary olfactory neurons.…”

“…Murrey et al (25) found using UEA-I affinity chromatography that 32 proteins including NCAM are ␣1-2-fucosylated in the OB, and Pestean et al (26) reported that NCAM is the main glycoprotein with ␣1-2Fuc glycan in the OB. We showed that the abundance of ␣1-2Fuc glycan associated with NCAM is diurnal, although the expression of Ncam1 mRNA and NCAM protein does not vary.…”

Localization of α1-2 Fucose Glycan in the Mouse Olfactory Pathway

“…Neuronal functions, such as learning and memory, as well as neuronal morphological changes, including neurite outgrowth and synaptic plasticity are mediated by α1-2 fucose (α1-2Fuc) glycan [Pohle et al, 1987;Krug et al, 1991Krug et al, , 1994Matthies et al, 1996;Lorenzini et al, 1997;Kalovidouris et al, 2005;Murrey et al, 2006]. Murrey et al [2009] found that development of the olfactory bulb is defective in mice with a deficiency of α1-2-specific fucosyltransferase 1, and we recently showed that the amount of α1-2Fuc glycan in the olfactory bulb diurnally fluctuates via rhythmic expression of the Fut1 gene [Kondoh et al, 2014]. Therefore, α1-2Fuc glycan might control functional changes in the olfactory system during developmental stages and circadian variations.…”

“…Although α1-2Fuc glycan has been histochemically localized in the mouse olfactory system using Ulex europaeus agglutinin-I (UEA-I) [Lundh et al, 1989;Ducray et al, 1999;Salazar et al, 2001;Lipscomb et al, 2002Lipscomb et al, , 2003Salazar and Sánchez Quinteiro, 2003;Murrey et al, 2009;Barrios et al, 2014;Kondoh et al, 2014], the findings are diverse. For example, we showed that α1-2Fuc glycan preferentially locates in the LOT and in the glomerular layer of the AOB of the ICR mouse [Kondoh et al, 2014] whereas other study groups have not found that UEA-I reacts with the mouse LOT.…”

Proteomics of the Synapse – A Quantitative Approach to Neuronal Plasticity

“…Likewise to the lectin-based approaches for the characterization of the O-and N-linked glycoproteomes, Murrey et al (165) used a more L-fucose-specific lectin from Ulex europaeus to enrich for fucosylated protein from different brain regions of adult and P3 mice. The 32 identified candidates belong to the classes of cell adhesion molecules, ion channels and solute carriers/transporters, ATP-binding proteins, synaptic-vesicle associated proteins and mitochondrial proteins, and most of them are predominantly expressed and developmentally regulated in the olfactory bulb.…”