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Genomics and Applied Biology
, 2013, Vol. 4 No.1 1-7
http://gab.sophiapublisher.com
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Functional Analysis of a type-2C Protein Phosphatase (AtPP2C52) in
Arabidopsis
thaliana
Hua Liu
1
, Daisuke Tsugama
1
,
Shenkui Liu
2
, Tetsuo Takano
1
,
1. Asian Natural Environmental Science Center (ANESC), The University of Tokyo, Tokyo, 188-0002, Japan
2. Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin 150040, P.R. China
Corresponding author:
Authors
Genomics and Applied Biology 2013, Vol.4 No.1 doi: 10.5376/gab.2013.04.0001
Received: 18 Dec., 2012
Accepted: 24 Dec., 2012
Published: 30 Jan., 2013
Copyright
© 2013 Liu et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
Liu et al., 2013, Functional analysis of a type
-
2C protein phosphatase (AtPP2C52) in
Arabidopsis thaliana
, Genomics and Applied Biology, 2013, Vol.4 No.1
1-7 (doi: 10.3969/gab.2013.04.0001)
Abstract
AtPP2C52 is a plasma membrane type
-
2C protein phosphatase. In this study, AtPP2C52 promoter-GUS analysis revealed
that AtPP2C52 gene was found in a broad expression spectrum with a higher level in the vascular and meristem. AtPP2C52 can
interact with multiple proteins, including a proteasome maturation factor, UMP1, and a cysteine proteinase, RD21a, as well as the
heterotrimeric G proteins β subunit, AGB1. By mutational analysis of AtPP2C52, it was identified that some residues were essential
for AtPP2C52 to bind AGB1, UMP1 and RD21a, suggesting that these proteins should be potential substrates of AtPP2C52.
Keywords
Protein phosphatase; Vascular; Protein-protein interaction,
Arabidopsis thaliana
Background
Protein phosphorylation regulates almost all aspect of
cell life (Hunter, 1998; Cohen, 1997). In Arabidopsis
genome, 112 protein phosphatases have been
identified (Kerk et al., 2002). Protein phosphatases
have been considered to be much more flexible
enzymes, which have a larger number of substrates
and present with overlapping activities (Lammers and
Lavi, 2007).
Based on the substrate specificity and on the conser-
vation of the catalytic domain, protein phosphatases
were grouped into protein serine/threonine (Ser/Thr)
phosphatases and protein tyrosine phosphatases.
Protein Ser/Thr phosphatases were classified into
phosphoprotein phosphatases (PPPs) and metal-
dependent protein phophatases (PPMs). The PPM
family contains type-2C protein phosphatase (PP2C)
subfamily and pyruvate dehydrogenase phosphatase
(Cohen, 1997).
PP2Cs were found in all organisms, such as plants,
bacteria, yeast, nematodes, insects, and mammals
(Schweighofer et al., 2004). A distinguishing feature
of PP2Cs is the requirement of bivalent cation (Mn
2+
or Mg
2+
) for their catalytic activity. Meanwhile, the
intracellular concentrations of Mg
2+
and Mn
2+
do not
fluctuate substantially under physiological conditions.
Therefore, the activities of PP2Cs may controlled
predominantly by their tissue- or cell type-specific
expression, subcellular compartmentalization, post-
translational modification, or/and degradation (Lam-
mers and Lavi, 2007).
In Arabidopsis, seventy-six PP2C genes were
identified (Kerk et al., 2002). These genes were
clustered into several groups, based on their sequence
similarity (Schweighofer et al., 2004; Xue et al., 2008).
Group A PP2C genes are annotated as negative
regulators of the ABA response in plant (Hirayama
and Shinozaki, 2007). On the other hand, SNF1-
related protein kinase 2 (SnRK2) family, which is
activated by ABA or osmotic stress, positively
regulates the ABA response in various tissues
(Mustilli et al., 2002; Yoshida et al., 2002; Fujii et al.,
2007). Group A PP2Cs interacted physically with
SnRK2s in various combinations, and efficiently
inactivated SnRK2s via dephosphorylation of multiple
Ser/Thr residues in the activation loop (Umezawa et
al., 2009). In response to ABA, PP2C-dependent
negative regulation can be canceled by ABA receptors,
RCAR/PYRs, leading to activation of positive
regulatory pathways (Ma et al., 2009; Park et al.,
2009). Group A PP2Cs interacted physically with
RCAR/PYRs. Members of Group B PP2C were
shown to regulate stomata aperture, seed germination,
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