2024-03-28T11:29:00Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1327382021-12-28T16:27:01Zcom_10261_80com_10261_1col_10261_333
Raynaud, Sandy
Ragel, Paula
Mérida, Ángel
2016-05-30T09:30:21Z
2016-05-30T09:30:21Z
2016
Journal of Biological Chemistry, 291(20): 10759-107771 (2016)
http://hdl.handle.net/10261/132738
10.1074/jbc.M115.698332
26969163
Starch synthase 4 (SS4) plays a specific role in starch synthesis
because it controls the number of starch granules synthesized in
the chloroplast and is involved in the initiation of the starch
granule. We showed previously that SS4 interacts with fibrillins
1 and is associated with plastoglobules, suborganelle compartments
physically attached to the thylakoid membrane in chloroplasts.
Both SS4 localization and its interaction with fibrillins
1 were mediated by the N-terminal part of SS4. Here we
show that the coiled-coil region within the N-terminal portion
of SS4 is involved in both processes. Elimination of this
region prevents SS4 from binding to fibrillins 1 and alters SS4
localization in the chloroplast. We also show that SS4 forms
dimers, which depends on a region located between the
coiled-coil region and the glycosyltransferase domain of SS4.
This region is highly conserved between all SS4 enzymes
sequenced to date.Weshow that the dimerization seems to be
necessary for the activity of the enzyme. Both dimerization
and the functionality of the coiled-coil region are conserved
among SS4 proteins from phylogenetically distant species,
such as Arabidopsis and Brachypodium. This finding suggests
that the mechanism of action of SS4 is conserved among different
plant species.
eng
openAccess
The N-terminal Part of Arabidopsis thaliana Starch Synthase 4 Determines the Localization and Activity of the Enzyme
artículo