TY - JOUR
T1 - Killing of Trypanosoma brucei by Concanavalin A
T2 - Structural basis of resistance in glycosylation mutants
AU - Acosta-Serrano, Alvaro
AU - Cole, Robert N.
AU - Englund, Paul T.
N1 - Funding Information:
This !ork !as supported by N = grant A 21**4 (to P"T"E")" A"A"-S" !as supported in part by a postdoctoral fello!ship from Consejo Nacional de nvestigaciones Cient́õficas y Tecnológicas, CON C T (Venezuela), and R"N"C" by the American =ealth Assistance Foundation" We are especially indebted to Mike Ferguson and Angela Mehlert for their generous contribution in the initial part of this project and for fruitful discussions" We also appreciate substantial input and valuable advice from Jay <angs" We thank gor Almeida, >uo-Yuan =!a, David Jiang, Michele >lingbeil, Sharon >rag, Yasu Mori-ta, >im Paul, Terry Pearson, and sabel Roditi for helpful discussions and for critical reading of the manuscript"
PY - 2000/12/8
Y1 - 2000/12/8
N2 - Concanavalin A (Con A) kills procyclic (insect) forms of Trypanosoma brucei by binding to N-glycans on EP-procyclin, a major surface glycosyl phosphatidylinositol (GPI)-anchored protein which is rich in Glu-Pro repeats. We have previously isolated and studied two procyclic mutants (ConA 1-1 and ConA 4-1) that are more resistant than wild-type (WT) to Con A killing. Although both mutants express the same altered oligosaccharides compared to WT cells, ConA 4-1 is considerably more resistant to lectin killing than is ConA 1-1. Thus, we looked for other alterations to account for the differences in sensitivity. Using mass spectrometry, together with chemical and enzymatic treatments, we found that both mutants express types of EP-procyclin that are either poorly expressed or not found at all in WT cells. ConA 1-1 expresses mainly EP1-3, a novel procyclin that contains 18 EP repeats, is partially N-glycosylated, and bears hybrid-type glycans. On the other hand, ConA 4-1 cells express almost exclusively EP2-3, a novel non-glycosylated procyclin isoform with 23 EP repeats and no site for glycosylation. The predominance of EP2-3 in ConA 4-1 cells explains their high resistance to ConA killing. Thus, switching the procyclin repertoire, a process that could be relevant to parasite development in the insect vector, modulates the sensitivity of trypanosomes to cytotoxic lectins. (C) 2000 Academic Press.
AB - Concanavalin A (Con A) kills procyclic (insect) forms of Trypanosoma brucei by binding to N-glycans on EP-procyclin, a major surface glycosyl phosphatidylinositol (GPI)-anchored protein which is rich in Glu-Pro repeats. We have previously isolated and studied two procyclic mutants (ConA 1-1 and ConA 4-1) that are more resistant than wild-type (WT) to Con A killing. Although both mutants express the same altered oligosaccharides compared to WT cells, ConA 4-1 is considerably more resistant to lectin killing than is ConA 1-1. Thus, we looked for other alterations to account for the differences in sensitivity. Using mass spectrometry, together with chemical and enzymatic treatments, we found that both mutants express types of EP-procyclin that are either poorly expressed or not found at all in WT cells. ConA 1-1 expresses mainly EP1-3, a novel procyclin that contains 18 EP repeats, is partially N-glycosylated, and bears hybrid-type glycans. On the other hand, ConA 4-1 cells express almost exclusively EP2-3, a novel non-glycosylated procyclin isoform with 23 EP repeats and no site for glycosylation. The predominance of EP2-3 in ConA 4-1 cells explains their high resistance to ConA killing. Thus, switching the procyclin repertoire, a process that could be relevant to parasite development in the insect vector, modulates the sensitivity of trypanosomes to cytotoxic lectins. (C) 2000 Academic Press.
KW - Glycosyl phosphatidylinositol
KW - Mass spectrometry
KW - N-glycosylation
KW - Procyclin
KW - Trypanosome
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U2 - 10.1006/jmbi.2000.4246
DO - 10.1006/jmbi.2000.4246
M3 - Article
C2 - 11099385
AN - SCOPUS:0034624085
VL - 304
SP - 633
EP - 644
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 4
ER -