User:John Samuelson

John Samuelson received his M.D. and Ph.D. in Cell and Developmental Biology from Harvard Medical School. As a post-doctoral fellow and faculty member at the Harvard School of Public Health, he discovered extensive horizontal gene transfer from bacteria and a cryptic mitochondrion-derived organelle in Entamoeba histolytica, the protist that causes dysentery and liver abscess. With his move to Boston University, Dr. Samuelson got his real introduction to glycobiology in a 15 year collaboration with Phil Robbins. Together they showed the major cyst wall proteins of Entamoeba are chitin-binding lectins and identified CBM55 at the N-terminus of the chitinase [1, 2, 3]. They showed that the most abundant cyst wall proteins of Giardia lamblia, cause of diarrhea, have Leu-rich repeats that bind to fibrils of the unique β-1,3-linked GalNAc polymer [4]. They demonstrated β-1,3-glucan in the inner layer of the oocyst wall of Toxoplasma gondii, cause of birth defects, and identified a unique glucan-binding domain at the N-terminus of the GH17 glycoside hydrolase [5]. In a separate line of experiments, Drs. Samuelson and Robbins showed that secondary loss of genes encoding Alg enzymes explains the diversity of N-glycan precursors among eukaryotes [6], demonstrated Darwinian selection for N-glycan sites in secreted proteins of the vast majority of eukaryotes that have N-glycan-dependent quality control of glycoprotein folding in the ER lumen [7], and identified N-glycans of Entamoeba, Giardia, and Plasmodium falciparum (cause of malaria) [8, 9, 10]. With Giulia Bandini they discovered a large set of nuclear proteins of Toxoplasma that are decorated with O-linked fucose [11] and with Chris West showed that the O-fucosyltransferase is a homolog of plant Spindly, which contains TPR and GT41 domains [12]. Recently, Dr. Samuelson with Breeanna Urbanowicz showed the most abundant proteins in the cyst wall of Acanthamoeba castellanii, cause of blindness, are cellulose- and chitin-binding lectins [13].

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1. Frisardi M, Ghosh SK, Field J, Van Dellen K, Rogers R, Robbins P, and Samuelson J. (2000). The most abundant glycoprotein of amebic cyst walls (Jacob) is a lectin with five Cys-rich, chitin-binding domains. Infect Immun. 2000;68(7):4217-24. DOI:10.1128/IAI.68.7.4217-4224.2000 |
2. Van Dellen K, Ghosh SK, Robbins PW, Loftus B, and Samuelson J. (2002). Entamoeba histolytica lectins contain unique 6-Cys or 8-Cys chitin-binding domains. Infect Immun. 2002;70(6):3259-63. DOI:10.1128/IAI.70.6.3259-3263.2002 |
3. Chatterjee A, Ghosh SK, Jang K, Bullitt E, Moore L, Robbins PW, and Samuelson J. (2009). Evidence for a "wattle and daub" model of the cyst wall of entamoeba. PLoS Pathog. 2009;5(7):e1000498. DOI:10.1371/journal.ppat.1000498 |
4. Chatterjee A, Carpentieri A, Ratner DM, Bullitt E, Costello CE, Robbins PW, and Samuelson J. (2010). Giardia cyst wall protein 1 is a lectin that binds to curled fibrils of the GalNAc homopolymer. PLoS Pathog. 2010;6(8):e1001059. DOI:10.1371/journal.ppat.1001059 |
5. Bushkin GG, Motari E, Magnelli P, Gubbels MJ, Dubey JP, Miska KB, Bullitt E, Costello CE, Robbins PW, and Samuelson J. (2012). β-1,3-glucan, which can be targeted by drugs, forms a trabecular scaffold in the oocyst walls of Toxoplasma and Eimeria. mBio. 2012;3(5). DOI:10.1128/mBio.00258-12 |
6. Samuelson J, Banerjee S, Magnelli P, Cui J, Kelleher DJ, Gilmore R, and Robbins PW. (2005). The diversity of dolichol-linked precursors to Asn-linked glycans likely results from secondary loss of sets of glycosyltransferases. Proc Natl Acad Sci U S A. 2005;102(5):1548-53. DOI:10.1073/pnas.0409460102 |
7. Cui J, Smith T, Robbins PW, and Samuelson J. (2009). Darwinian selection for sites of Asn-linked glycosylation in phylogenetically disparate eukaryotes and viruses. Proc Natl Acad Sci U S A. 2009;106(32):13421-6. DOI:10.1073/pnas.0905818106 |
8. Magnelli P, Cipollo JF, Ratner DM, Cui J, Kelleher D, Gilmore R, Costello CE, Robbins PW, and Samuelson J. (2008). Unique Asn-linked oligosaccharides of the human pathogen Entamoeba histolytica. J Biol Chem. 2008;283(26):18355-64. DOI:10.1074/jbc.M800725200 |
9. Ratner DM, Cui J, Steffen M, Moore LL, Robbins PW, and Samuelson J. (2008). Changes in the N-glycome, glycoproteins with Asn-linked glycans, of Giardia lamblia with differentiation from trophozoites to cysts. Eukaryot Cell. 2008;7(11):1930-40. DOI:10.1128/EC.00268-08 |
10. Bushkin GG, Ratner DM, Cui J, Banerjee S, Duraisingh MT, Jennings CV, Dvorin JD, Gubbels MJ, Robertson SD, Steffen M, O'Keefe BR, Robbins PW, and Samuelson J. (2010). Suggestive evidence for Darwinian Selection against asparagine-linked glycans of Plasmodium falciparum and Toxoplasma gondii. Eukaryot Cell. 2010;9(2):228-41. DOI:10.1128/EC.00197-09 |
11. Bandini G, Haserick JR, Motari E, Ouologuem DT, Lourido S, Roos DS, Costello CE, Robbins PW, and Samuelson J. (2016). O-fucosylated glycoproteins form assemblies in close proximity to the nuclear pore complexes of Toxoplasma gondii. Proc Natl Acad Sci U S A. 2016;113(41):11567-11572. DOI:10.1073/pnas.1613653113 |
12. Gas-Pascual E, Ichikawa HT, Sheikh MO, Serji MI, Deng B, Mandalasi M, Bandini G, Samuelson J, Wells L, and West CM. (2019). CRISPR/Cas9 and glycomics tools for Toxoplasma glycobiology. J Biol Chem. 2019;294(4):1104-1125. DOI:10.1074/jbc.RA118.006072 |
13. Magistrado-Coxen P, Aqeel Y, Lopez A, Haserick JR, Urbanowicz BR, Costello CE, and Samuelson J. (2019). The most abundant cyst wall proteins of Acanthamoeba castellanii are lectins that bind cellulose and localize to distinct structures in developing and mature cyst walls. PLoS Negl Trop Dis. 2019;13(5):e0007352. DOI:10.1371/journal.pntd.0007352 |