SCF^SNIPER4 controls the turnover of two redundant TRAF proteins in plant immunity

Abstract

In mammals, tumor necrosis factor receptor associated factors (TRAFs) are signaling adaptors that regulate diverse physiological processes, including immunity and stress responses. In Arabidopsis, MUSE13 and MUSE14 are redundant TRAF proteins serving as adaptors in the SCF complex to facilitate the turnover of nucleotide-binding domain and leucine-rich repeats (NLR) immune receptors. Degradation of MUSE13 is inhibited by proteasome inhibitor, suggesting that the MUSE13 stability is controlled by the 26S proteasome. However, the E3 ligase that regulates MUSE13 level is unknown. Here we report the identification of an F-box protein, SNIPER4 that regulates the turnover of MUSE13 and MUSE14. Protein levels of MUSE13 and MUSE14 are reduced by SNIPER4 overexpression, while higher accumulation of MUSE13 and MUSE14 is observed when dominant-negative SNIPER4 is expressed. Furthermore, SNIPER4 associates with MUSE13 or MUSE14. Taken together, the SCF complex controls the turnover of TRAF proteins for an optimum immune output.

Arabidopsis SINAT Proteins Control Autophagy by Mediating Ubiquitylation and Degradation of ATG13

“…Although we have confirmed that ATG1s were involved in the phosphorylation-like modification of TRAF1a in vitro, the shift in molecular weight of TRAF1a may also be caused by other larger posttranslational modifications. Consistent with this, a recent study revealed that the degradation of both TRAF1a and TRAF1b is mediated by the SCF SNIPER4 complex to control the turnover of TRAF1 proteins in plant cells (Huang et al, 2018). Thus, further investigations of the interaction of posttranslational modifications, such as ubiquitylation and phosphorylation, in determining the stability of TRAF1 proteins will be needed to better understand the molecular mechanism of TRAF1 proteins in the regulation of autophagy initiation.…”

Diverse and dynamic roles of F-box proteins in plant biology

“…Interestingly, overexpression of SNIPER4 enhanced the accumulation of SNC1 and knockout of SNIPER4 reduced the accumulation of SNC1, suggesting its role as a positive regulator in plant immunity. This phenomenon showcases the complex turnover regulation of NLR immune response by SCF SNIPER4 through the control of protein MUSE13/14 homeostasis (Huang et al 2018).…”

“…Another FBP screened from Arabidopsis, snc1-influencing plant E3 ligase reverse genetic (SNIPER), which was designated SNIPER4, was shown to negatively regulate MUTANT, SNC1-ENHANCING (MUSE) 13 and 14, a type of tumour necrosis factor receptor associated factor (TRAF) in plants (Huang et al 2018) serving as an adaptor in the SCF CPR1 complex (Huang et al 2016). SNIPER4 interactions with ASK1 and MUSE13/14 were confirmed through the split luciferase complementation assay.…”

The Mediator kinase module serves as a positive regulator of salicylic acid accumulation and systemic acquired resistance

“…PCR products were digested with SfiI and then ligated into either pCambia1300-35S-HA-Cluc or pCambia1300-35S-HA-Nluc vectors. Split-luciferase complementation assays was conducted as previously described (Huang et al, 2018). sity) for generously sharing the pCBC DT1T2 and pHEE401E constructs.…”