MEK/ERK inhibitor U0126 enhanced salt stress-induced programmed cell death in Thellungiella halophila suspension-cultured cells

Abstract

Programmed cell death (PCD) is an active cellular suicide that occurs both in animals and plants throughout development and in response to abiotic or biotic stress. In contrast to plant hypersensitive response-like cell death, little is known about the molecular machinery that regulates the halophyte plant PCD under high salinity stress. Since mitogen-activated protein kinases (MAPKs) are involved in plant response/tolerance to salt stress, and plant MAPK genes belong to the extracellular signalregulated kinase (ERK) subfamily, we have investigated the role of ERK-like enzymes in high salinity stress-induced cell death in Thellungiella halophila. The data showed that ERK-like enzymes were early (10 min) and transiently activated under 300 mM NaCl stress. Pretreatment with 10 lM U0126, a special MEK/ERK inhibitor, resulted in a small but statistically significant increase of the percentage of terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL)-positive nuclei in contrast to salt alone. The effects of U0126 on H 2 O 2 production and cytochrome c (cyt c) release were also investigated. We found that the pretreatment with U0126 accelerated H 2 O 2 production as well as cyt c release, and eventually enhanced cell death. The results suggest that ERK-like enzymes in Thellungiella halophila may act as a positive regulator of salt tolerance, as illustrated by pretreatment with U0126 which enhanced cell death under high salinity stress.

Differential Activity of Plasma and Vacuolar Membrane Transporters Contributes to Genotypic Differences in Salinity Tolerance in a Halophyte Species, Chenopodium quinoa

“…Maintenance of a high cytosolic K + is not only important for the activity of a large number of cytosolic enzymes [46], but is also essential for suppressing the activity of caspase-like proteases and endonucleases in plant cells [47–49]. If depletion in the cytosolic K + pool cannot be prevented, protein catabolism takes place, resulting in programmed cell death (PCD) [48,50].…”

Aluminum induces rapidly mitochondria-dependent programmed cell death in Al-sensitive peanut root tips

“…Cytosolic fractions from Al-treated root tip cells were used to assay caspase3-like protease (Wang et al [ 2010 ]), according to the manufacturer’s instruction (Caspase-3 Activity Assay Kit, `Beyotime, China). Protein concentration was determined by Bradford’s method ([ 1976 ]).…”

“…Similar to animal cells, plant cells can also respond to various stimuli, including biotic and abiotic stresses as well as development by initiating PCD (Wang et al [ 2011 ]). PCD is associated with specific morphological and biochemical features such as nuclear DNA degradation (Achary and Panda [ 2010 ]; Fu et al [ 2003 ]; Qiao et al [ 2003 ]), specific proteases activation (Poor et al [ 2013 ]), plasma membrane embolus or chromatin condensation (Wang et al [ 2012 ]), Cyt c release from mitochondria to cytoplasm (Wang et al [ 2010 ]), mitochondrial permeability transition pore (MPTP) opening and mitochondrial membrane potential collapse (Panda et al [ 2008 ]; Toninello et al [ 2000 ]). Increasing evidences show that Al-induced PCD plays a significant role in Al tolerance of plants, animals and yeasts (Wang et al [ 2009 ]; Yakimova et al [ 2007 ]; Zheng et al [ 2007 ]).…”

Signaling pathway in development of Camellia oleifera nurse seedling grafting union

“…MAPK signaling pathways are known to play a central role in cell proliferation, differentiation, apoptosis, and development (Weihs et al 2014), and belong to the extracellular signal-regulated kinase (ERK) subfamily (Wang et al 2011). Multiple MAPK pathways exist in one cell, and each pathway is linked to different upstream signals and downstream substrates.…”