A novel domain in the protein kinase SOS2 mediates interaction with the protein phosphatase 2C ABI2. Proc Natl Acad Sci U S A

Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 10/2003; 100(20):11771-6. DOI: 10.1073/pnas.2034853100
Source: PubMed


SOS2 (salt overly sensitive 2) is a serine/threonine protein kinase required for salt tolerance in Arabidopsis thaliana. In this study, we identified the protein phosphatase 2C ABI2 (abscisic acid-insensitive 2) as a SOS2-interacting protein. Deletion analysis led to the discovery of a novel protein domain of 37 amino acid residues, designated as the protein phosphatase interaction (PPI) motif, of SOS2 that is necessary and sufficient for interaction with ABI2. The PPI motif is conserved in protein kinases of the SOS2 family (i.e., protein kinase S, PKS) and in the DNA damage repair and replication block checkpoint kinase, Chk1, from various organisms including humans. Mutations in the conserved amino acid residues in the PPI motif abolish the interaction of SOS2 with ABI2. We also identified a protein kinase interaction domain in ABI2 and examined the interaction specificity between PKS and the ABI phosphatases. We found that some PKSs interact strongly with ABI2 whereas others interact preferentially with ABI1. The interaction between SOS2 and ABI2 was disrupted by the abi2-1 mutation, which causes increased tolerance to salt shock and abscisic acid insensitivity in plants. Our results establish the PPI motif and the protein kinase interaction domain as novel protein interaction domains that mediate the binding between the SOS2 family of protein kinases and the ABI1/2 family of protein phosphatases.

26 Reads
  • Source
    • "SOS1 protein is the direct target of SOS signaling pathway, and it is regulated through protein phosphorylation by the alternative SOS2/ SOS3 and SOS2/CBL10 protein kinase complexes (Qiu et al. 2002; Quintero et al. 2002, 2011; Quan et al. 2007). ABI2 is the negative regulatory of this pathway, through the inhibition of SOS2 kinase activity or the activity of SOS2 targets, suggesting a cross talk between the ABA pathway and SOS pathway (Ohta et al. 2003). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Salinity is a major environmental stress that limits agriculture production. Hence, it is essential to produce salt-tolerant crops for sustaining food production. Understanding the molecular basis of salt-stress signaling and tolerance mechanisms is essential for breeding and genetic engineering of salt tolerance in crop plants. Plant adaptation or tolerance to salinity stress involves complex physiological traits, metabolic pathways, and molecular or gene networks. In many plants, the salt tolerance is associated with the ability to exclude sodium from the shoot, to prevent its accumulation in pho-tosynthetic tissues. Salinity stress involves changes in various physiological and metabolic processes, depending on severity and duration of the stress, and ultimately inhibits crop production. In this chapter, we mainly discuss about the effect of salinity on plants and tolerance mechanisms that permit the plants to withstand stress.
    Managing Salt Tolerance In Plant: Molecular and Genomic Perspectives, 2015 edited by Shabir Hussain Wani and Mohammad Anwar Hossain, 10/2015: chapter Understanding Plant Stress Response and Tolerance to Salinity from Gene to Whole Plant: pages 1-18; CRCnetBASE., ISBN: 978-1-4822-4513-4
  • Source
    • "Like typical of protein kinases, the N-terminal catalytic domain has ATP binding site and activation loop. The C-terminal regulatory domain contains FISL or NAF motifs that mediates interaction with CBLs [1,54–56] and other motif called as PPI motif, mediates interaction with type 2C protein phosphates [57]. All of the OsCIPKs contained catalytic kinase domain and NAF domain. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Calcium ion is involved in diverse physiological and developmental pathways. One of the important roles of calcium is a signaling messenger, which regulates signal transduction in plants. CBL (calcineurin B-like protein) is one of the calcium sensors that specifically interact with a family of serine–threonine protein kinases designated as CBL-interacting protein kinases (CIPKs). The coordination of these two gene families defines complexity of the signaling networks in several stimulus-response-coupling during various environmental stresses. In Arabidopsis, both of these gene families have been extensively studied. To understand in-depth mechanistic interplay of CBL–CIPK mediated signaling pathways, expression analysis of entire set of CBL and CIPK genes in rice genome under three abiotic stresses (salt, cold and drought) and different developmental stages (3-vegetative stages and 11-reproductive stages) were done using microarray expression data. Interestingly, expression analysis showed that rice CBLs and CIPKs are not only involved in the abiotic stress but their significant role is also speculated in the developmental processes. Chromosomal localization of rice CBL and CIPK genes reveals that only OsCBL7 and OsCBL8 shows tandem duplication among CBLs whereas CIPKs were evolved by many tandem as well as segmental duplications. Duplicated OsCIPK genes showed variable expression pattern indicating the role of gene duplication in the extension and functional diversification of CIPK gene family in rice. Arabidopsis SOS3/CBL4 related genes in rice (OsCBL4, OsCBL5, OsCBL7 and OsCBL8) were employed for interaction studies with rice and Arabidopsis CIPKs. OsCBLs and OsCIPKs are not only found structurally similar but likely to be functionally equivalent to Arabidopsis CBLs and CIPKs genes since SOS3/CBL4 related OsCBLs interact with more or less similarly to rice and Arabidopsis CIPKs and exhibited an interaction pattern comparable with Arabidopsis SOS3/CBL4.
    Cell Calcium 08/2014; 56(2). DOI:10.1016/j.ceca.2014.05.003 · 3.51 Impact Factor
  • Source
    • "The same research group reported that SOS2 (a type of CIPKs) forms a complex with SOS3 (a type of CBL proteins), and lead to activation of SOS1 (a Na+/H+ antiporter) important for ion homeostasis and salt tolerance. In this SOS pathway, ABI2 (a type of PP2C) act as a negative regulator by deactivating SOS2 or dephosphorylating SOS1 [38]. The network seems to fairly well represent the CBL-CIPK-PP2C interactions among genes involved in the Ca2+-mediated signaling, although their modes of action, such as activation and deactivation, are not denoted. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cross-species translation of genomic information may play a pivotal role in applying biological knowledge gained from relatively simple model system to other less studied, but related, genomes. The information of abiotic stress (ABS)-responsive genes in Arabidopsis was identified and translated into the legume model system, Medicago truncatula. Various data resources, such as TAIR/AtGI DB, expression profiles and literatures, were used to build a genome-wide list of ABS genes. tBlastX/BlastP similarity search tools and manual inspection of alignments were used to identify orthologous genes between the two genomes. A total of 1,377 genes were finally collected and classified into 18 functional criteria of gene ontology (GO). The data analysis according to the expression cues showed that there was substantial level of interaction among three major types (i.e., drought, salinity and cold stress) of abiotic stresses. In an attempt to translate the ABS genes between these two species, genomic locations for each gene were mapped using an in-house-developed comparative analysis platform. The comparative analysis revealed that fragmental colinearity, represented by only 37 synteny blocks, existed between Arabidopsis and M. truncatula. Based on the combination of E-value and alignment remarks, estimated translation rate was 60.2% for this cross-family translation. As a prelude of the functional comparative genomic approaches, in-silico gene network/interactome analyses were conducted to predict key components in the ABS responses, and one of the sub-networks was integrated with corresponding comparative map. The results demonstrated that core members of the sub-network were well aligned with previously reported ABS regulatory networks. Taken together, the results indicate that network-based integrative approaches of comparative and functional genomics are important to interpret and translate genomic information for complex traits such as abiotic stresses.
    PLoS ONE 03/2014; 9(3):e91721. DOI:10.1371/journal.pone.0091721 · 3.23 Impact Factor
Show more

Preview (2 Sources)

26 Reads
Available from