Effect of catalytic subunit phosphorylation on the properties of SnRK1 from Phaseolus vulgaris embryos
Por:
Zúñiga-Sánchez E., Rodriguez-Sotres, Rogelio, Coello, Patricia, Martinez-Barajas, Eleazar
Publicada:
1 mar 2019
Resumen:
Legume seed development represents a high demand for energy and
metabolic resources to support the massive synthesis of starch and
proteins. However, embryo growth occurs in an environment with reduced
O-2 that forces the plant to adapt its metabolic activities to maximize
efficient energy use. SNF1-related protein kinase1 (SnRK1) is a master
metabolic regulator needed for cells adaptation to conditions that
reduce energy availability, and its activity is needed for the
successful development of seeds. In bean embryo extracts, SnRK1 can be
separated by anion exchange chromatography into two pools: one where the
catalytic subunit is phosphorylated (SnRK1-p) and another with reduced
phosphorylation (SnRK1-np). The phosphorylation of the catalytic subunit
produces a large increase in SnRK1 activity but has a minor effect in
determining its sensitivity to metabolic inhibitors such as trehalose
6-P (T6P), ADP-glucose (ADPG), glucose 1-P (G1P) and glucose 6-P (G6P).
In Arabidopsis thaliana, upstream activating kinases (SnAK)
phosphorylate the SnRK1 catalytic subunit at T175/176, promoting and
enhancing its activity. Recombinant Phaseolus vulgaris homologous to
SnAK proteins (PvSnAK), can phosphorylate and activate the catalytic
domains of the alpha-subunits of Arabidopsis, as well as the SnRK1-np
pool purified from bean embryos. While the phosphorylation process is
extremely efficient for catalytic domains, the phosphorylation of the
SnRK1-np complex was less effective but produced a significant increase
in activity. The presence of SnRK1-np could contribute to a quick
response to unexpected adverse conditions. However, in addition to
PvSnAK kinases, other factors might contribute to regulating the
activation of SnRK1.
Filiaciones:
Zúñiga-Sánchez E.:
Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM)DF 04510, Mexico
Rodriguez-Sotres, Rogelio:
Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM)DF 04510, Mexico
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
Coello, Patricia:
Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM)DF 04510, Mexico
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
Martinez-Barajas, Eleazar:
Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México (UNAM)DF 04510, Mexico
Univ Nacl Autonoma Mexico, Fac Quim, Dept Bioquim, Mexico City 04510, DF, Mexico
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