Turnover and shedding of the Tc-85 surface glycoprotein of Trypanosoma cruzi trypomastigotes.
Tc-85 is an 85-kDa surface glycoprotein specific for the trypomastigote stage of Trypanosoma cruzi which has been implicated in the invasion of host cells by the parasite. Tc-85 has a half-life of 3.5-4 h and is synthesized as a 95-kDa precursor. Processing of the 95-kDa precursor is inhibited by N-p-tosyl-L-lysine chloromethyl ketone, p-chloromercuriphenylsulfonic acid, iodoacetamide or N-ethylmaleimide, but not by aprotinin, antipain or phenylmethylsulfonil fluoride. Tc-85, but not the precursor, is rapidly shed into the medium, allowing a correlation between the decrease of Tc-85 in trypomastigotes and its increase in the culture medium. The shedding of Tc-85 was inhibited 50% by 1 microM tunicamycin, but not by 10 microM swainsonine or 10 microM 1-deoxynojirimycin under the experimental conditions employed. This suggests that N-linked oligosaccharides are important for the shedding phenomenon, although it appears that they do not have to be fully processed for shedding to occur.
Abuin
G
G
Departamento de Bioquímica, Universidade de São Paulo, Brasil.
Colli
W
W
Alves
M J
MJ
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D014349:Trypanosoma cruzi / Q000378:metabolism*; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000096:biosynthesis / Q000187:drug effects* / Q000378:metabolism
D014643:Variant Surface Glycoproteins, Trypanosoma