EL5 is involved in root development as an anti-cell death ubiquitin ligase

Abstract

Ubiquitin ligase (E3) plays a central role in substrate recognition during ubiquitination, a post-translational modification of proteins. Rice EL5 is an E3 with a RING-H2 finger domain (RFD) and its transcript is upregulated by a chitin elicitor. The EL5-RFD has been intensively studied and demonstrated to exhibit E3 activity. Its three-dimensional structure was determined for the first time in plant E3, and the amino acid residues required for the interaction with the ubiquitin-conjugating enzyme (E2) were identified. Recent analyses revealed that EL5 plays a crucial role as an E3 in the maintenance of cell viability during root development in rice. In this addendum, we report that the EL5-RFD catalyzes polyubiquitination via the Lys48 residue of ubiquitin. We also discuss the possible role of EL5 as an anti-cell death enzyme. We hypothesize that EL5 might be responsible for mediating the degradation of cytotoxic proteins produced in root cells after the actions of phytohormones.

The RING finger E3 ligase STRF1 is involved in membrane trafficking and modulates salt‐stress response in Arabidopsis thaliana

“…All members of the ATL family contain a RING-finger domain. Indeed, up to now, three members of the ATL family, ATL2, ATL9 and ATL31, have been shown to be active E3 ligases in Arabidopsis (Serrano et al, 2006;Nishizawa et al, 2008;Sato et al, 2009;Berrocal-Lobo et al, 2010). To test whether STRF1 also has ubiquitin ligase activity, we carried out an in vitro ubiquitination assay.…”

“…STRF1 belongs to the Arabidopsis ATL (Arabidopsis Toxicos en Levadura) gene family, whose members, if overexpressed in yeast, cause a conditional lethal phenotype (Aguilar-Henonin et al, 2006). The ATL protein family from Arabidopsis contains 80 members, all characterized by the presence of a conserved RING-H2 type finger, which has been shown to be active for ATL31, ATL9 and EL5 (Serrano et al, 2006;Koiwai et al, 2007;Nishizawa et al, 2008;Sato et al, 2009;Berrocal-Lobo et al, 2010). Some ATL members have been also functionally characterized and shown to play a role in diverse plant processes ranging from plant defense (ATL2 and ATL9; Berrocal-Lobo et al, 2010;Serrano and Guzman, 2004), to carbon/nitrogen response for growth phase transition (ATL31; Sato et al, 2009), to ABA sensitivity (ATL43; Serrano et al, 2006).…”

Profiling Gene Expression in Germinating Brassica Roots

“…The upregulation of UBQ in RS (position # 5) preceded the development of root hairs. UBQ is linked to root and lateral root development (Nodzon et al 2004 ; Nishizawa et al 2008 ; Prasad et al 2010 ; von Schaewen et al 1990 ) and changes related to these processes question the suitability of this gene as reference gene. Our results showed upregulation of ACT7 and TUB in EZ (positions # 2 and 3), indicating that elongation growth of roots correlates with the expression of cytoskeleton proteins.…”

OsATL32 ubiquitinates the reactive oxygen species‐producing OsRac5–OsRbohB module to suppress rice immunity

“…The Arabidopsis Tóxicos En Levadura (ATL) subfamily of RING‐type E3 ubiquitin ligases contain a transmembrane (TM) domain in addition to the canonical RING domain (Guzmán, 2012; Wu et al, 2023b). Although certain ATL family members have been implicated in plant immunity, including the Arabidopsis proteins AtATL2, AtATL6, AtATL9, AtATL31, and AtATL55/AtRING1 and the rice proteins BTH‐INDUCED RING FINGER PROTEIN 1 (OsBIRF1) and ELICITOR 5 (EL5) (Takai et al, 2001; Serrano and Guzmán, 2004; Lin et al, 2008; Nishizawa et al, 2008; Maekawa et al, 2012; Guo et al, 2022), the functions and underlying molecular mechanisms of the ATLs in plant disease resistance require further elucidation.…”