Regulation of plant carbon assimilation metabolism by post‐translational modifications

Abstract

The flexibility of plant growth, development and stress responses is choreographed by an intricate network of signaling cascades and genetic programs. However, it is metabolism that ultimately executes these programs through the selective delivery of specific building blocks and energy. Photosynthetic carbon fixation is the central pillar of the plant metabolic network, the functioning of which is conditioned by environmental fluctuations. Hence, regulation of carbon assimilation metabolism must be particularly versatile and rapid to maintain efficiency and avoid dysfunction. While changes in gene expression can adjust the global inventory and abundance of relevant proteins, their specific characteristics are dynamically altered at the post-translational level. Here we highlight studies that show the extent of the regulatory impact by posttranslational modification (PTM) on carbon assimilation metabolism. We focus on examples for which there has been empirical evidence of functional changes associated with a PTM, rather than just the occurrence of PTMs at specific sites in proteins, as regularly detected in proteomic studies. The examples indicate that we are only at the beginning of deciphering the PTM-based regulatory network that operates in plant cells. However, it is becoming increasingly clear that targeted exploitation of PTM engineering has the potential to control the metabolic flux landscape as a prerequisite for increasing crop yields, modifying metabolite composition, optimizing stress tolerance, and even executing novel growth and developmental programs.

The interplay of post‐translational protein modifications in Arabidopsis leaves during photosynthesis induction

“…The maximal extent of oxidation or reduction was detected rapidly, in most cases at t5 (Figure 7c). Light‐ and thioredoxin‐dependent reduction of CBC enzymes is established for GAPDH, SBPASE, PRK, and FBPASE (Balparda et al., 2023; Michelet et al., 2013). For three of the four proteins, we found peptides that are significantly and strongly reduced at t5 and which retained a similar level of reduction over time.…”

“…In the context of dark to light transition in plants, redox regulation of several CBC enzymes in the chloroplast stroma is probably the most prominent example for PTM‐based regulation of metabolism (Balparda et al., 2023; Buchanan, 2016; Michelet et al., 2013; Wirtz et al., 1982). The activity of four key enzymes of the CBC as well as the closely related α‐isoform of the RUBISCO ACTIVASE (RCA) are regulated by thioredoxin f‐dependent dithiol reduction (Michelet et al., 2013; Zhang & Portis, 1999).…”

Protein Phosphorylation Nexus of Cyanobacterial Adaptation and Metabolism

“…The carboxysome shell regulates the influx of bicarbonate and RuBP, while carbonic anhydrases within it convert bicarbonate to CO 2 , providing a high-CO 2 microenvironment for Rubisco. Additionally, the intricate interaction between the CO 2 availability and the phosphorylation of specific polypeptides implies a regulatory framework aimed at fine-tuning carbon assimilation in response to dynamic environmental cues [78].…”