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The Arabidopsis ALF 4 protein is a regulator of SCF E3 ligases
Author(s) -
Bagchi Rammyani,
Melnyk Charles W,
Christ Gideon,
Winkler Martin,
Kirchsteiner Kerstin,
Salehin Mohammad,
Mergner Julia,
Niemeyer Michael,
Schwechheimer Claus,
Calderón Villalobos Luz Irina A,
Estelle Mark
Publication year - 2017
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.15252/embj.201797159
Subject(s) - plant biology , library science , arabidopsis , plant science , biology , computer science , genetics , botany , gene , mutant
The cullin‐ RING E3 ligases ( CRL s) regulate diverse cellular processes in all eukaryotes. CRL activity is controlled by several proteins or protein complexes, including NEDD 8, CAND 1, and the CSN . Recently, a mammalian protein called Glomulin ( GLMN ) was shown to inhibit CRL s by binding to the RING BOX ( RBX 1) subunit and preventing binding to the ubiquitin‐conjugating enzyme. Here, we show that Arabidopsis ABERRANT LATERAL ROOT FORMATION 4 ( ALF 4) is an ortholog of GLMN . The alf4 mutant exhibits a phenotype that suggests defects in plant hormone response. We show that ALF 4 binds to RBX 1 and inhibits the activity of SCF TIR 1 , an E3 ligase responsible for degradation of the Aux/ IAA transcriptional repressors. In vivo , the alf4 mutation destabilizes the CUL 1 subunit of the SCF . Reduced CUL 1 levels are associated with increased levels of the Aux/ IAA proteins as well as the DELLA repressors, substrate of SCF SLY 1 . We propose that the alf4 phenotype is partly due to increased levels of the Aux/ IAA and DELLA proteins.