INGEBI   02650
INSTITUTO DE INVESTIGACIONES EN INGENIERIA GENETICA Y BIOLOGIA MOLECULAR "DR. HECTOR N TORRES"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Role of phosphorylation on the silencing suppressor activity of the movement protein TGBp1 of the Potato X virus and the relationship with its ATPase activity
Autor/es:
M. BINAGHI, N. MÓDENA, A. MENTABERRY, A. ZELADA
Lugar:
Quebec, Canadá
Reunión:
Congreso; XIV International Congress in Molecular Plant-Microbe Interactions; 2009
Institución organizadora:
International Society of Molecular Plant-Microbe Interactions
Resumen:
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Potato
virus X (PVX) is a member of the potexvirus whose RNA genome
codes
for the viral replicase, three movement proteins (MPs: TGBp1, TGBp2
and
TGBp3) and the viral capsid protein. Mounting evidence suggests that
phosphorylation
events can regulate MP functions. We have previously
demonstrated
that PVX TGBp1 is phosphorylated by a Nicotiana tabacum
CK2-like kinase (Módena et al.,
2008). The aim of this project is to evaluate
the
role of phosphorylation on the silencing suppressor and ATPase activities
of
the PVX TGBp1. Based on in silico analysis of sequences from different
potexvirus
TGBp1s, we identified two threonine residues possibly subjected
to
phosphorylation. We have developed different TGBp1 mutants where the
identified
threonines (T193 and T215) have been replaced by alanine (A) or
aspartate
(D) residues. Silencing experiments show that the TGBp1-T215A
mutant
is partially defective on its silencing suppressor activity whereas
TGBp1-T215D
loses all silencing suppressor activity. On the other hand, we
observed
that TGBp1-T193A has less suppressor activity due to the fact that it
is
less stable than wild-type TGBp1. We also show that although protein levels
of
TGBp1-T193D mutant are normal, it was not able to restore wild-type suppressor
activity.
Finally, ATP hydrolysis assays show that the ATPase activities
of
TGBp1-T193A and TGBp1-T215A were similar to wild-type TGBp1,
whereas
the revertant versions were significantly reduced. These results suggest
that
phosphorylation of PVX TGBp1 plays an important role in regulating the
ATPase activity which might be necessary for silencing suppression.