Salt-induced subcellular kinase relocation and seedling susceptibility caused by overexpression of Medicago SIMKK in Arabidopsis

Abstract

SummaryThis study revealed activation-dependent and coordinated relocation of Medicago sativa SIMKK and SIMK after salt stress. Arabidopsis seedlings stably overexpressing YFP-tagged SIMKK showed altered salt sensitivity and proteome changes.

Manipulation of Mitogen-Activated Protein Kinase Kinase Signaling in the Arabidopsis Stomatal Lineage Reveals Motifs That Contribute to Protein Localization and Signaling Specificity

“…Stomatal clustering was correlated with CAMKK7/9 displaying mitochondrial colocalization, while all MKK variants incapable of promoting stomatal clustering (CAMKK7/9ΔD and all CAMKK4/5 variants) showed alternative subcellular localization patterns in all stomatal lineage cell types. Recent findings indicate that in plants, similar to other eukaryotes, relocalization of MAPK components upon activation is needed for proper signal output (Ove cka et al, 2014). Here, we show that mitochondrial localization and kinase activity are required for MKK7/9 to promote stomatal clustering.…”

“…CAMKK4/5, which are incapable of inducing stomatal clustering in the FAMA stage, also do not localize to mitochondria (Supplemental Figures 9B and 9C). A recent report described localization of MPKs to punctate structures in response to activation (Ove cka et al, 2014). To test whether mitochondrial localization of CAMKK7 is a property of their constitutive activation or, alternatively, of their kinase activity, we monitored the localization of nonmodified MKK7-YFP and kinaseinactive (KI), yet constitutively active, variants (KI-CAMKK7-YFP) that fail to impact stomatal development at any stage.…”

“…We know primarily from studies in animals and yeast that MAPK signal fidelity can be generated through posttranslational modifications of the MAPKs, availability of physical association partners, subcellular localization of signaling proteins, and by modulating the amplitude and duration of signals from active kinases (reviewed in Saito, 2010;Wimmer and Baccarini, 2010;Wortzel and Seger, 2011;Ove cka et al, 2014). Each of these mechanisms is dependent upon specific protein-protein interactions.…”

Role of the Plasma Membrane in Saline Conditions: Lipids and Proteins

“…However, inhibition of the expression of the atRPK1 gene in Arabidopsis improved salt tolerance. Overexpression of Medicago sativa stress-induced MAPKK (SIMKK)-SIMK in Arabidopsis also exhibited high salt sensitivity (Ovečka et al, 2014). Increased salt sensitivity of the transgenic plants has been found to be consistent with their proteome composition.…”

Integrating cell biology and proteomic approaches in plants

“…Mitogen activated protein kinases are proteins involved in salt stress response of plants [83]. Stress induced mitogen activated protein kinase kinase (SIMKK) relocates from nucleus to cytosol during salt stress [84] in Medicago sativa, but also when heterologously expressed in Arabidopsis plants as chimeric protein tagged with yellow fluorescent protein (YFP). Such Arabidopsis plants overexpressing SIMKK-YFP exhibited increased sensitivity against salt stress.…”