13 May 2019

Signal peptide recognition in Trypanosoma cruzi GP82 adhesin relies on its localization at protein N-terminus.

DOI : 10.1038/s41598-019-43743-0

Cristian Cortez, PhD.

Trypanosoma cruzi, the causative agent of Chagas disease, has a dense coat of

GPI-anchored virulence factors. T. cruzi GPI-anchored adhesin GP82 is encoded by

a repertoire of transcripts containing several in-frame initiation codons

located up-stream from that adjacent to the predicted signal peptide (SP).

Transfection of T. cruzi epimastigotes with constructs encoding GP82 starting at

the SP or from the farthest up-stream methionine confirmed protein expression on

the parasite cell surface, comparable to the native GP82. Proteins were fully

functional, inducing parasite adhesion to HeLa cells and lysosome mobilization,

events required for parasite invasion. Transgenic and native GP82 proteins

showed indistinguishable electrophoretic mobility, suggesting similar processing

of the SP. Deletion of SP generated a ~72 kDa protein devoid of N-linked

oligosaccharides allowing irrefutable identification of GP82 precursor. SP

transposition to an internal region of GP82 rendered the signal unrecognizable

by the signal peptidase and incapable to direct the nascent protein for

ER-membrane association. Altogether our data strongly suggests that GP82 SP

fails to function as transmembrane domain and its recognition by the signal

peptidase shows strict dependence on the signal localization at protein

N-terminus. This report presents the first experimental characterization of the

full-length GP82 and its signal peptide.

Participating Center Researchers

Host-Pathogen Interactions Laboratory

PhD in Sciences, mention Microbiology, Inmunology, and Parasitology, Universidade Federal de São Paulo, Brasil.



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