Noncanonical mono(ADP-ribosyl)ation of zinc finger SZF proteins counteracts ubiquitination for protein homeostasis in plant immunity. Academic Article uri icon


  • Protein ADP-ribosylation is a reversible post-translational modification that transfers ADP-ribose from NAD+ onto acceptor proteins. Poly(ADP-ribosyl)ation (PARylation), catalyzed by poly(ADP-ribose) polymerases (PARPs) and poly(ADP-ribose) glycohydrolases (PARGs), which remove the modification, regulates diverse cellular processes. However, the chemistry and physiological functions of mono(ADP-ribosyl)ation (MARylation) remain elusive. Here, we report that Arabidopsis zinc finger proteins SZF1 and SZF2, key regulators of immune gene expression, are MARylated by the noncanonical ADP-ribosyltransferase SRO2. Immune elicitation promotes MARylation of SZF1/SZF2 via dissociation from PARG1, which has an unconventional activity in hydrolyzing both poly(ADP-ribose) and mono(ADP-ribose) from acceptor proteins. MARylation antagonizes polyubiquitination of SZF1 mediated by the SH3 domain-containing proteins SH3P1/SH3P2, thereby stabilizing SZF1 proteins. Our study uncovers a noncanonical ADP-ribosyltransferase mediating MARylation of immune regulators and underpins the molecular mechanism of maintaining protein homeostasis by the counter-regulation of ADP-ribosylation and polyubiquitination to ensure proper immune responses.

published proceedings

  • Mol Cell

altmetric score

  • 9.45

author list (cited authors)

  • Kong, L., Feng, B., Yan, Y., Zhang, C., Kim, J. H., Xu, L., ... He, P.

citation count

  • 14

complete list of authors

  • Kong, Liang||Feng, Baomin||Yan, Yan||Zhang, Chao||Kim, Jun Hyeok||Xu, Lahong||Rack, Johannes Gregor Matthias||Wang, Ying||Jang, Jyan-Chyun||Ahel, Ivan||Shan, Libo||He, Ping

publication date

  • January 2021