TY - JOUR
T1 - N-linked glycosylation modulates golgi-independent vacuolar sorting mediated by the plant specific insert
AU - Vieira, Vanessa
AU - Peixoto, Bruno
AU - Costa, Mónica
AU - Pereira, Susana
AU - Pissarra, José
AU - Pereira, Cláudia
N1 - Publisher Copyright:
© 2019 by the authors.
PY - 2019/8/30
Y1 - 2019/8/30
N2 - In plant cells, the conventional route to the vacuole involves the endoplasmic reticulum, the Golgi and the prevacuolar compartment. However, over the years, unconventional sorting to the vacuole, bypassing the Golgi, has been described, which is the case of the Plant-Specific Insert (PSI) of the aspartic proteinase cardosin A. Interestingly, this Golgi-bypass ability is not a characteristic shared by all PSIs, since two related PSIs showed to have different sensitivity to ER-to-Golgi blockage. Given the high sequence similarity between the PSI domains, we sought to depict the differences in terms of post-translational modifications. In fact, one feature that draws our attention is that one is N-glycosylated and the other one is not. Using site-directed mutagenesis to obtain mutated versions of the two PSIs, with and without the glycosylation motif, we observed that altering the glycosylation pattern interferes with the trafficking of the protein as the non-glycosylated PSI-B, unlike its native glycosylated form, is able to bypass ER-to-Golgi blockage and accumulate in the vacuole. This is also true when the PSI domain is analyzed in the context of the full-length cardosin. Regardless of opening exciting research gaps, the results obtained so far need a more comprehensive study of the mechanisms behind this unconventional direct sorting to the vacuole.
AB - In plant cells, the conventional route to the vacuole involves the endoplasmic reticulum, the Golgi and the prevacuolar compartment. However, over the years, unconventional sorting to the vacuole, bypassing the Golgi, has been described, which is the case of the Plant-Specific Insert (PSI) of the aspartic proteinase cardosin A. Interestingly, this Golgi-bypass ability is not a characteristic shared by all PSIs, since two related PSIs showed to have different sensitivity to ER-to-Golgi blockage. Given the high sequence similarity between the PSI domains, we sought to depict the differences in terms of post-translational modifications. In fact, one feature that draws our attention is that one is N-glycosylated and the other one is not. Using site-directed mutagenesis to obtain mutated versions of the two PSIs, with and without the glycosylation motif, we observed that altering the glycosylation pattern interferes with the trafficking of the protein as the non-glycosylated PSI-B, unlike its native glycosylated form, is able to bypass ER-to-Golgi blockage and accumulate in the vacuole. This is also true when the PSI domain is analyzed in the context of the full-length cardosin. Regardless of opening exciting research gaps, the results obtained so far need a more comprehensive study of the mechanisms behind this unconventional direct sorting to the vacuole.
KW - Aspartic proteinase
KW - Endoplasmic reticulum
KW - Golgi
KW - N-linked glycosylation
KW - Plant Specific Insert
KW - Unconventional trafficking
KW - Vacuolar sorting
UR - http://www.scopus.com/inward/record.url?scp=85073323519&partnerID=8YFLogxK
U2 - 10.3390/plants8090312
DO - 10.3390/plants8090312
M3 - Article
C2 - 31480247
AN - SCOPUS:85073323519
SN - 2223-7747
VL - 8
SP - 1
EP - 21
JO - Plants
JF - Plants
IS - 9
M1 - 312
ER -