» Articles » PMID: 25387872

Conserved Ion and Amino Acid Transporters Identified As Phosphorylcholine-modified N-glycoproteins by Metabolic Labeling with Propargylcholine in Caenorhabditis Elegans Cells

Overview
Journal Glycobiology
Date 2014 Nov 13
PMID 25387872
Citations 2
Authors
Affiliations
Soon will be listed here.
Abstract

Phosphorylcholine (PC) modification of proteins by pathogens has been implicated in mediating host-pathogen interactions. Parasitic nematodes synthesize PC-modified biomolecules that can modulate the host's antibody and cytokine production to favor nematode survival, contributing to long-term infections. Only two nematode PC-modified proteins (PC-proteins) have been unequivocally identified, yet discovering the protein targets of PC modification will be paramount to understanding the role(s) that this epitope plays in nematode biology. A major hurdle in the field has been the lack of techniques for selective purification of PC-proteins. The nonparasitic nematode Caenorhabditis elegans expresses PC-modified N-linked glycans, offering an attractive model to study the biology of PC-modification. We developed a robust method to identify PC-proteins by metabolic labeling of primary embryonic C. elegans cells with propargylcholine, an alkyne-modified choline analog. Cu(I)-catalyzed cycloaddition with biotin-azide enables streptavidin purification and subsequent high-throughput LC-MS identification of propargyl-labeled proteins. All proteins identified using stringent criteria are known or predicted to be membrane or secreted proteins, consistent with the model of a Golgi-resident, putative PC-transferase. Of the 55 PC-N-glycosylation sites reported, 33 have been previously observed as N-glycosylation sites in high-throughput screens of C. elegans. Several identified PC-proteins are nematode-specific proteins, but 10 of the PC-proteins are widely conserved ion transporters and amino acid transporters, while eight are conserved proteins involved in synaptic function. This finding suggests a functional role for PC-modification beyond immunomodulation. The approach presented in this study provides a method to identify PC-proteins in C. elegans and related nematodes.

Citing Articles

Metabolic labeling of glycerophospholipids via clickable analogs derivatized at the lipid headgroup.

Ancajas C, Ricks T, Best M Chem Phys Lipids. 2020; 232:104971.

PMID: 32898510 PMC: 7606648. DOI: 10.1016/j.chemphyslip.2020.104971.


The PCome of Ascaris suum as a model system for intestinal nematodes: identification of phosphorylcholine-substituted proteins and first characterization of the PC-epitope structures.

Timm T, Grabitzki J, Severcan C, Muratoglu S, Ewald L, Yilmaz Y Parasitol Res. 2016; 115(3):1263-74.

PMID: 26728072 DOI: 10.1007/s00436-015-4863-7.

References
1.
Gerdt S, Dennis R, Borgonie G, Schnabel R, Geyer R . Isolation, characterization and immunolocalization of phosphorylcholine-substituted glycolipids in developmental stages of Caenorhabditis elegans. Eur J Biochem. 1999; 266(3):952-63. DOI: 10.1046/j.1432-1327.1999.00937.x. View

2.
Lee M, Cram E, Shen B, Schwarzbauer J . Roles for beta(pat-3) integrins in development and function of Caenorhabditis elegans muscles and gonads. J Biol Chem. 2001; 276(39):36404-10. DOI: 10.1074/jbc.M105795200. View

3.
Keller A, Nesvizhskii A, Kolker E, Aebersold R . Empirical statistical model to estimate the accuracy of peptide identifications made by MS/MS and database search. Anal Chem. 2002; 74(20):5383-92. DOI: 10.1021/ac025747h. View

4.
Cipollo J, Costello C, Hirschberg C . The fine structure of Caenorhabditis elegans N-glycans. J Biol Chem. 2002; 277(51):49143-57. DOI: 10.1074/jbc.M208020200. View

5.
Haslam S, Dell A . Hallmarks of Caenorhabditis elegans N-glycosylation: complexity and controversy. Biochimie. 2003; 85(1-2):25-32. DOI: 10.1016/s0300-9084(03)00041-5. View