Table 1.
N-glycan-dependent QC of glycoprotein folding and ERAD in representative eukaryotes
| Organisms | N-glycan | Folding |
Degradation |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Gls2 | UGGT | CRT* | CNX* | ERGIC | Mns1† | EDEM† | Yos9 | PNGase | ||
| Sc/Sp | Glc3Man9GlcNAc2 | Y | N‡/Y | N | Y | Y | Y | Y | Y | Y |
| Hs/At/Dd | Glc3Man9GlcNAc2 | Y | Y | Y | Y | Y | Y | Y | Y | Y |
| Cn | Man9GlcNAc2 | Y | Y§ | N | Y | Y | Y | Y | Y | Y |
| Lm/Tb/Tc | Man7–9GlcNAc2 | Y | Y | Y | N | Y | N | N/Y/Y¶ | Y | N |
| Eh/Tv | Man5GlcNAc2 | Y‖ | Y§ | Y | N/Y | Y | N/Y** | N | N/Y | N/Y†† |
| Tt/Tg/Cp | Glc1–3Man5GlcNAc2 | Y | N | N | N/Y‡‡/N | N | N | N | N | N |
| Pf/Gl | GlcNAc2 | N | N | N | N | N | N | N | N | N |
| Ec/Ta | None | N | N | N | N | Y/N | N | N | N | N |
Organisms are grouped by confirmed or predicted N-glycan precursors (4). Sc, S. cerevisiae; Sp, S. pombe; Hs, Homo sapiens; At, Arabidopsis thaliana; Dd, D. discoideum; Cn, C. neoformans; Lm, L. major; Tb, T. brucei; Tc, T. cruzi; Eh, E. histolytica; Tv, T. vaginalis; Tt, T. thermophila; Tg, T. gondii; Cp, C. parvum; Pf, P. falciparum; Gl, G. lamblia; Ec, E. cuniculi; Ta, T. annulata.
*A phylogenetic analysis of CRT and CNX is shown in Fig. 3A.
†A phylogenetic analysis of Mns1 and EDEM is shown in Fig. 3B.
‡Sc Kre5 is orthologous to UGGT but does not have the same function (7).
¶The mannosidase activity of the Trypanosoma EDEM ortholog is shown in Fig. 6.
‖The function of the Trichomonas glucosidase 2 is demonstrated indirectly with its inhibitor, castanospermine, in Fig. 4B.
**The mannosidase activity of a Trichomonas Mns1 is shown in Fig. 7 B–D.
††The N-glycanase activity of the Trichomonas cytosolic PNGase is shown in Fig. 7A.
‡‡The Toxoplasma CNX is missing most of the arm that binds PDI [supporting information (SI) Fig. 8].