Poly(ADP-Ribose) Polymerases in Plants and Their Human Counterparts: Parallels and Peculiarities

Abstract

Poly(ADP-ribosyl)ation is a rapid and transient post-translational protein modification that was described first in mammalian cells. Activated by the sensing of DNA strand breaks, poly(ADP-ribose)polymerase1 (PARP1) transfers ADP-ribose units onto itself and other target proteins using NAD+ as a substrate. Subsequently, DNA damage responses and other cellular responses are initiated. In plants, poly(ADP-ribose) polymerases (PARPs) have also been implicated in responses to DNA damage. The Arabidopsis genome contains three canonical PARP genes, the nomenclature of which has been uncoordinated in the past. Albeit assumptions concerning the function and roles of PARP proteins in planta have often been inferred from homology and structural conservation between plant PARPs and their mammalian counterparts, plant-specific roles have become apparent. In particular, PARPs have been linked to stress responses of plants. A negative role under abiotic stress has been inferred from studies in which a genetic or, more commonly, pharmacological inhibition of PARP activity improved the performance of stressed plants; in response to pathogen-associated molecular patterns, a positive role has been suggested. However, reports have been inconsistent, and the effects of PARP inhibitors appear to be more robust than the genetic abolition of PARP gene expression, indicating the presence of alternative targets of those drugs. Collectively, recent evidence suggests a conditionality of stress-related phenotypes of parp mutants and calls for a reconsideration of PARP inhibitor studies on plants. This review critically summarizes our current understanding of poly(ADP-ribosylation) and PARP proteins in plants, highlighting similarities and differences to human PARPs, areas of controversy, and requirements for future studies.

The Arabidopsis thaliana Poly(ADP-Ribose) Polymerases 1 and 2 Modify DNA by ADP-Ribosylating Terminal Phosphate Residues

“…Noteworthy, the double parp1 parp2 mutant of Arabidopsis showed more rapid primary and lateral root growth, suggesting that plant PARPs inhibit mitosis and promote cell differentiation (Liu et al, 2017). Based on these observations, it was proposed that PARPs influence plant development only under specific conditions the nature of which requires further investigations (Rissel and Peiter, 2019).…”

Investigation of the three-dimensional structure and interaction mechanism of poly (ADP-ribose) polymerase 4

“…The overall folding of PARP1, PARP2 and PARP4 confirms similarity in catalytic domains but can differ in substrate proteins. Similar and different domains are expected to occur because even plant and human PARP proteins have similar and different regions when compared [23]. However, the discovery of these regions can shed light on some experimental results.…”

Unravelling Differences in Candidate Genes for Drought Tolerance in Potato (Solanum tuberosum L.) by Use of New Functional Microsatellite Markers

“…Drought stress can lead to DNA lesions including double strand breaks (DSBs) as a major form [ 78 , 79 , 80 ]. DNA damage surveillance and repair processes have to recruit a number of repair proteins including poly (ADP-ribose) polymerases (PARPs), which recognize DNA SSBs and DSBs, assemble DNA repair complexes and auto-PARylate [ 81 , 82 ]. As the PARylation process is reversible, ADP-ribose chains are eventually hydrolyzed by the enzyme poly (ADP-ribose) glycohydrolase (PARG) [ 83 ].…”