The stomatal phosphoenolpyruvate carboxylase — a potential target for selective proteolysis during stomatal closure?

Klockenbring, Torsten; Meinhard, Michael; Schnabl, Heide

doi:10.1016/s0176-1617(98)80136-3

Cited by 8 publications

(4 citation statements)

References 36 publications

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“…PEPC also appears to be a target of ubiquitination, which would promote enzyme proteolysis during stomatal closure. Like phosphorylation, this posttranslational modification also is linked to ABA in a process mediated by the second messenger inositol 1,4,5-trisphosphate, which accumulates during ABA-induced stomatal closure (Lee et al, 1996;Klockenbring et al, 1998). Interestingly, inositol 1,4,5-trisphosphate also has been implicated in the regulation of K + channels and Ca 2+ signaling (Blatt et al, 1990;Gilroy et al, 1990), highlighting the key role of ABA in the coordinated activation of membrane ion transport and the associated metabolic activities required for stomatal closure.…”

Section: Synthesis Of Malate and Its Catabolism In Guard Cellsmentioning

confidence: 99%

Rethinking Guard Cell Metabolism

2016

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ORCID IDs: 0000-0001-9686-1216 (D.S.); 0000-0002-4073-7221 (T.L.).Stomata control gaseous fluxes between the internal leaf air spaces and the external atmosphere and, therefore, play a pivotal role in regulating CO 2 uptake for photosynthesis as well as water loss through transpiration. Guard cells, which flank the stomata, undergo adjustments in volume, resulting in changes in pore aperture. Stomatal opening is mediated by the complex regulation of ion transport and solute biosynthesis. Ion transport is exceptionally well understood, whereas our knowledge of guard cell metabolism remains limited, despite several decades of research. In this review, we evaluate the current literature on metabolism in guard cells, particularly the roles of starch, sucrose, and malate. We explore the possible origins of sucrose, including guard cell photosynthesis, and discuss new evidence that points to multiple processes and plasticity in guard cell metabolism that enable these cells to function effectively to maintain optimal stomatal aperture. We also discuss the new tools, techniques, and approaches available for further exploring and potentially manipulating guard cell metabolism to improve plant water use and productivity.

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Section: Synthesis Of Malate and Its Catabolism In Guard Cellsmentioning

confidence: 99%

Rethinking Guard Cell Metabolism

2016

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“…4). Recently, PEPC from castor (Ricinus communis) oil seeds was shown to be monoubiquitinated (Uhrig et al, 2008), and PEPC polyubiquitination resulting in proteolysis has also been reported (Klockenbring et al, 1998). While ubiquitination in general is known to affect PM binding (Mukhopadhyay and Riezman, 2007), it is not known whether ubiquitination of PEPC would affect its cellular localization.…”

Section: A Role For Membrane-surface Charge In Regulating Pepc Activimentioning

confidence: 99%

Phosphoenolpyruvate Carboxylase from C4 Leaves Is Selectively Targeted for Inhibition by Anionic Phospholipids

Monreal

McLoughlin²,

Echevarrı́a³

et al. 2009

Plant Physiology

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“…A variety of proteolytic activities have been proposed for the degradation of other PEPC variants in different plant cell types. It has been hypothesized that the proteolysis of C 3 -PEPC in guard cells during their closing phase of action may be dependent on the ubiquitin-proteasome system (Klockenbring et al, 1998). In addition, a C 3 -PEPC in castor oil seeds is degraded in vitro via a thiol endopeptidase requiring dithiothreitol and salt to remove its N -terminus thereby generating a 98 kDa PEPC fragmented form (Crowley et al, 2005; Uhrig et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Anionic Phospholipids Induce Conformational Changes in Phosphoenolpyruvate Carboxylase to Increase Sensitivity to Cathepsin Proteases

et al. 2019

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Phosphoenolpyruvate carboxylase (PEPC) is a cytosolic, homotetrameric enzyme that serves a variety of functions in plants, acting as the primary form of CO 2 fixation in the C 4 photosynthesis pathway (C 4 -PEPC). In a previous work we have shown that C 4 -PEPC bind anionic phospholipids, resulting in PEPC inactivation. Also, we showed that PEPC can associate with membranes and to be partially proteolyzed. However, the mechanism controlling this remains unknown. Using semi purified-PEPC from sorghum leaf and a panel of PEPC-specific antibodies, we analyzed the conformational changes in PEPC induced by anionic phospholipids to cause the inactivation of the enzyme. Conformational changes observed involved the exposure of the C -terminus of PEPC from the native, active enzyme conformation. Investigation of the protease activity associated with PEPC demonstrated that cysteine proteases co-purify with the enzyme, with protease-specific substrates revealing cathepsin B and L as the major protease species present. The anionic phospholipid-induced C-terminal exposed conformation of PEPC appeared highly sensitive to the identified cathepsin protease activity and showed initial proteolysis of the enzyme beginning at the N -terminus. Taken together, these data provide the first evidence that anionic phospholipids promote not only the inactivation of the PEPC enzyme, but also its proteolysis.

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The stomatal phosphoenolpyruvate carboxylase — a potential target for selective proteolysis during stomatal closure?

Cited by 8 publications

References 36 publications

Rethinking Guard Cell Metabolism

Rethinking Guard Cell Metabolism

Phosphoenolpyruvate Carboxylase from C4 Leaves Is Selectively Targeted for Inhibition by Anionic Phospholipids

Anionic Phospholipids Induce Conformational Changes in Phosphoenolpyruvate Carboxylase to Increase Sensitivity to Cathepsin Proteases

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