Unique N-Terminal Interactions Connect F-BOX STRESS INDUCED (FBS) Proteins to a WD40 Repeat-like Protein Pathway in Arabidopsis

Abstract

SCF-type E3 ubiquitin ligases provide specificity to numerous selective protein degradation events in plants, including those that enable survival under environmental stress. SCF complexes use F-box (FBX) proteins as interchangeable substrate adaptors to recruit protein targets for ubiquitylation. FBX proteins almost universally have structure with two domains: A conserved N-terminal F-box domain interacts with a SKP protein and connects the FBX protein to the core SCF complex, while a C-terminal domain interacts with the protein target and facilitates recruitment. The F-BOX STRESS INDUCED (FBS) subfamily of plant FBX proteins has an atypical structure, however, with a centrally located F-box domain and additional conserved regions at both the N- and C-termini. FBS proteins have been linked to environmental stress networks, but no ubiquitylation target(s) or biological function has been established for this subfamily. We have identified two WD40 repeat-like proteins in Arabidopsis that are highly conserved in plants and interact with FBS proteins, which we have named FBS INTERACTING PROTEINs (FBIPs). FBIPs interact exclusively with the N-terminus of FBS proteins, and this interaction occurs in the nucleus. FBS1 destabilizes FBIP1, consistent with FBIPs being ubiquitylation targets SCFFBS1 complexes. This work indicates that FBS proteins may function in stress-responsive nuclear events, and it identifies two WD40 repeat-like proteins as new tools with which to probe how an atypical SCF complex, SCFFBS, functions via FBX protein N-terminal interaction events.

Characterization key genes of Arabidopsis seedlings in response to β-caryophyllene, eugenol using combined transcriptome and WGCN analysis

“…In Petunia hybrida, PhCS plays a crucial role in the synthesis of chlorophylls, carotenoids, and anthocyanins ( Masson et al., 2019 ). The F-BOX STRESS INDUCED (FBS) proteins have been associated with environmental stress networks, and WD40 repeat-like proteins are known targets of SCFFFBSI complexes ( Sepulveda-Garcia et al., 2021 ). The up-regulation of LOX, CS , and LOX3 genes suggested that BCP induced stress and damaged the metabolic pathway.…”

What Makes the Life of Stressed Plants a Little Easier? Defense Mechanisms against Adverse Conditions

“…The F-BOX STRESS INDUCED (FBS) subfamily of plant FBX proteins has an abnormal structure, nevertheless, with an F-box domain placed in the center and extra conserved regions at the N-and C-termini. Sepulveda-Garcia et al [10] showed two WD40 repeat-like proteins in Arabidopsis that are highly conserved in plants and interact with FBS proteins, which were named FBS INTERACTING PROTEINs (FBIPs). FBIPs react only with the N-terminus of FBS proteins, and this interaction takes place in the nucleus.…”

The Identification and Analysis of the Self-Incompatibility Pollen Determinant Factor SLF in Lycium barbarum

“…These genes are collectively referred to as SLF genes in Solanaceae and Plantaginaceae or SFB genes in Rosaceae [31]. The N-terminus of SLF genes features an F-box domain, while the C-terminus possesses two highly variable regions (Hva and Hvb) that lack strong hydrophobicity and are primarily responsible for recognizing self and non-self S-RNase genes [32].…”