IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Complex formation regulates the glycosylation of the reversibly glycosylated polypeptide
Autor/es:
VERÓNICA DE PINO; MARIELA BORÁN; LORENA NORAMBUENA; MARIELA GONZALEZ; FRANCISCA REYES; ARIEL ORELLANA; SILVIA MORENO
Revista:
PLANTA
Editorial:
Springer-Verlag
Referencias:
Año: 2007 vol. 226 p. 335 - 345
ISSN:
0032-0935
Resumen:
Reversible glycosylated polypeptides (RGPs)
are highly conserved plant-specific proteins, which can
perform self-glycosylation. These proteins have been
shown essential in plants yet its precise function
remains unknown. In order to understand the function
of this self-glycosylating polypeptide, it is important to
establish what factors are involved in the regulation of
the RGP activity. Here we show that incubation at high
ionic strength produced a high self-glycosylation level
and a high glycosylation reversibility of RGP fromc proteins, which can
perform self-glycosylation. These proteins have been
shown essential in plants yet its precise function
remains unknown. In order to understand the function
of this self-glycosylating polypeptide, it is important to
establish what factors are involved in the regulation of
the RGP activity. Here we show that incubation at high
ionic strength produced a high self-glycosylation level
and a high glycosylation reversibility of RGP from
Solanum tuberosum L. In contrast, incubation at low
ionic strength led to a low level of glycosylation and a
low glycosylation reversibility of RGP. The incubation
at low ionic strength favored the formation of high
molecular weight RGP-containing forms, whereas
incubation at high ionic strength produced active RGP
with a molecular weight similar to the one expected for
the monomer. Our data also showed that glycosylation
of RGP, in its monomeric form, was highly reversible,
whereas, a low reversibility of the protein glycosylation
was observed when RGP was part of high molecular
weight structures. In addition, glycosylation of RGP
increased the occurrence of non-monomeric RGP-containing
forms, suggesting that glycosylation may favor
multimer formation. Finally, our results indicated that
RGP from Arabidopsis thaliana and Pisum sativum are
associated to golgi membranes, as part of protein complexes.
A model for the regulation of the RGP activity
and its binding to golgi membranes based on the glycosylation
of the protein is proposed where the sugars
linked to oligomeric form of RGP in the golgi may be
transferred to acceptors involved in polysaccharide
biosynthesis.L. In contrast, incubation at low
ionic strength led to a low level of glycosylation and a
low glycosylation reversibility of RGP. The incubation
at low ionic strength favored the formation of high
molecular weight RGP-containing forms, whereas
incubation at high ionic strength produced active RGP
with a molecular weight similar to the one expected for
the monomer. Our data also showed that glycosylation
of RGP, in its monomeric form, was highly reversible,
whereas, a low reversibility of the protein glycosylation
was observed when RGP was part of high molecular
weight structures. In addition, glycosylation of RGP
increased the occurrence of non-monomeric RGP-containing
forms, suggesting that glycosylation may favor
multimer formation. Finally, our results indicated that
RGP from Arabidopsis thaliana and Pisum sativum are
associated to golgi membranes, as part of protein complexes.
A model for the regulation of the RGP activity
and its binding to golgi membranes based on the glycosylation
of the protein is proposed where the sugars
linked to oligomeric form of RGP in the golgi may be
transferred to acceptors involved in polysaccharide
biosynthesis.Arabidopsis thaliana and Pisum sativum are
associated to golgi membranes, as part of protein complexes.
A model for the regulation of the RGP activity
and its binding to golgi membranes based on the glycosylation
of the protein is proposed where the sugars
linked to oligomeric form of RGP in the golgi may be
transferred to acceptors involved in polysaccharide
biosynthesis.