Dataset Information

The C-terminal domains SnRK2-box and ABA-box have a role in sugarcane SnRK2s auto-activation and activity

ABSTRACT: Resistance to drought stress is fundamental to plant survival and development. Abscisic acid (ABA) is one of the major hormones involved in different types of abiotic and biotic stress responses. ABA intracellular signaling has been extensively explored in Arabidopsis thaliana and occurs via a phosphorylation cascade mediated by three related protein kinases, denominated SnRK2s (SNF1-related protein kinases). However, the role of ABA signaling and the biochemistry of SnRK2 in crop plants remains underexplored. Considering the importance of the ABA hormone in abiotic stress tolerance, here we investigated the regulatory mechanism of sugarcane SnRK2s - known as SAPKs (Stress/ABA-activated Protein Kinases). The crystal structure of ScSAPK10 revealed the characteristic SnRK2 family architecture, in which the regulatory SnRK2-box interacts with the kinase domain αC helix. To study sugarcane SnRK2 regulation, we produced a series of mutants for the protein regulatory domains SnRK2-box and ABA-box. Surprisingly, mutations in the SnRK2-box did not drastically affect sugarcane SnRK2 activity, in contrast to previous observations for the homologous proteins in Arabidopsis. Also, we found that the ABA-box might have a role in SnRK2 activation in the absence of PP2C phosphatase. Taken together, our results demonstrate that both C-terminal domains of sugarcane SnRK2 proteins play a role in protein activation and activity.

INSTRUMENT(S): Xevo G2-S QTof

ORGANISM(S): Saccharum Hybrid Cultivar X Sorghum Bicolor

SUBMITTER: Dev Sriranganadane

LAB HEAD: Rafael Miguez Couñago

PROVIDER: PXD014298 | Pride | 2019-11-13

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	ScSAPK8_WT_AutoPhospho.mgf	Mgf
	ScSAPK8_WT_AutoPhospho.raw.zip	Raw
	ScSAPK8_WT_AutoPhospho_IA_final_fragment.csv	Csv
	ScSAPK8_WT_AutoPhospho_IA_final_peptide.csv	Csv
	ScSAPK8_WT_AutoPhospho_IA_final_protein.csv	Csv

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Publications

The C-Terminal Domains SnRK2 Box and ABA Box Have a Role in Sugarcane SnRK2s Auto-Activation and Activity.

Righetto Germanna Lima GL Sriranganadane Dev D Halabelian Levon L Chiodi Carla G CG Elkins Jonathan M JM Massirer Katlin B KB Gileadi Opher O Menossi Marcelo M Couñago Rafael M RM

Frontiers in plant science 20190917

Resistance to drought stress is fundamental to plant survival and development. Abscisic acid (ABA) is one of the major hormones involved in different types of abiotic and biotic stress responses. ABA intracellular signaling has been extensively explored in <i>Arabidopsis thaliana</i> and occurs <i>via</i> a phosphorylation cascade mediated by three related protein kinases, denominated SnRK2s (SNF1-related protein kinases). However, the role of ABA signaling and the biochemistry of SnRK2 in crop ...[more]

PMID: 31620147

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Project description:Abscisic acid (ABA) is a key hormone for plant growth, development and stress adaptation. Perception of ABA through four types of receptors has been reported. We show here that impairment of ABA perception through the PYR/PYL/RCAR branch reduces vegetative growth and seed production, and leads to a severely open stomata and dramatic ABA insensitive phenotype, even though other branches for ABA perception remain functional. Arabidopsis sextuple mutant impaired in 6 PYR/PYL receptors, namely PYR1, PYL1, PYL2, PYL4, PYL5 and PYL8, was able to germinate and grow even on 100 mM ABA. Whole-rosette stomatal conductance (Gst) measurements revealed that leaf transpiration in the sextuple pyr/pyl mutant was higher than in the ABA-deficient aba3-1 or ABA-insensitive snrk2.6 mutants. The gradually increasing Gst values of plants lacking three, four, five and six PYR/PYLs indicate quantitative regulation of stomatal aperture by this family of receptors. The sextuple mutant lacked ABA-mediated activation of SnRK2s and ABA-responsive gene expression was dramatically impaired as was reported in snrk2.2/2.3/2.6. In summary, these results show that ABA perception by PYR/PYLs plays a major role to regulate seed germination and establishment, basal ABA signaling required for vegetative and reproductive growth, stomatal aperture and transcriptional response to the hormone. Four biological replicates were generated for the 3 genotypes, pyr1pyl1pyl2pyl4pyl5pyl8 sextuple mutant, snrk2.2/2.3/2.6 triple mutant, and Col-0. All the samples were treated with ABA for 3 hours before harvesting. The four Col-0 samples were mix to create an unique reference Col-0 sample. Two comparasion were made, fisrt one, PYR/PYL sextuple mutant versus Col-0 reference sample and second one, SnRK2 triple mutant versus Col-0 reference sample. In each comparasion four biological replicates were made. Replicas number 1 and 2 were labeled with Cy5 for the mutant sample and Cy3 for the Col-0 reference sample, while the other two replicas,#3 and #4, were reversed-labeled.

Project description:The rapid activation of RAF-SnRK2 cascades in response to hyperosmolarity is a crucial event in plants' adaptation to osmotic stress, yet the underlying mechanisms have remained elusive. In this study, we reveal that the calcium chelator EGTA, but not other calcium modulators, can potently activate both RAFs and SnRK2s. We demonstrate that EGTA induces the phosphorylation of RAF24, serving as an indicator of rapid RAF activation. Furthermore, we show that EGTA treatment results in increased phosphorylation of Ser171 and Ser175 in SnRK2.6, known markers of SnRK2 activation. In-gel kinase assays confirmed the activation of RAFs and SnRK2s. These findings collectively highlight that exogenous EGTA application mimics mannitol treatment, effectively triggering the activation of both RAF and SnRK2 subfamily kinases. Utilizing a DIA-based phosphoproteomics approach, we profiled global phosphorylation changes in response to EGTA and mannitol treatments. We identified 22,991 phosphorylated peptides corresponding to 6,515 phosphosites on 1,790 proteins. Notably, 5,067 sites were classified as class I phosphorylation sites, indicating high confidence in their localization. Principal Component Analysis confirmed the distinct phosphoproteomic profiles of the three conditions, with excellent reproducibility among biological replicates. EGTA treatment induced substantial changes in global phosphorylation, with 3,987 phosphosites increased and 964 decreased, signifying a profound impact on protein phosphorylation. The activation of RAFs and SnRK2s was supported by significant phosphorylation changes in these kinases. Additionally, EGTA-induced phosphoproteins included downstream effectors of RAF-SnRK2 cascades. GO analysis revealed distinct functional categories for EGTA and mannitol-responsive phosphoproteins, shedding light on the divergent roles of these treatments. Our study provides novel insights into the role of EGTA in the activation of RAF-SnRK2 cascades and its broader impact on the plant phosphoproteome, offering a valuable resource for understanding the downstream events related to exocellular calcium depletion in plants. It also highlights the potential involvement of MAP4Ks and resistosome-related kinases in osmotic stress signaling. Overall, our research enhances our understanding of osmotic stress response mechanisms and the power of DIA-based phosphoproteomics in unraveling complex phosphorylation events in plants.