Structural highlights
Function
ARFE_ARATH Auxin response factors (ARFs) are transcriptional factors that binds specifically to the DNA sequence 5'-TGTCTC-3' found in the auxin-responsive promoter elements (AuxREs). Seems to act as transcriptional activator. Formation of heterodimers with Aux/IAA proteins may alter their ability to modulate early auxin response genes expression. Mediates embryo axis formation and vascular tissues differentiation. Functionally redundant with ARF7. May be necessary to counteract AMP1 activity.[1] [2] [3]
Publication Abstract from PubMed
Auxin is a plant hormone that is central to plant growth and development from embryogenesis to senescence. Auxin signaling is mediated by auxin response transcription factors (ARFs) and Aux/IAA repressors that regulate the expression of a multitude of auxin response genes. ARF and Aux/IAA proteins assemble into homomeric and heteromeric complexes via their conserved PB1 domains. Here we report the first crystal structure of the PB1 complex between ARF5 and IAA17 of Arabidopsis thaliana, which represents the transcriptionally repressed state at low auxin levels. The PB1 domains assemble in a head-to-tail manner with a backbone arrangement similar to that of the ARF5:ARF5 PB1 complex. The ARF5:IAA17 complex, however, reveals distinct points of contact that promote the ARF5:IAA17 interaction over the ARF5:ARF5 interaction. Specifically, surface charges at the interface form salt-bridges that distinguish the homomeric and heteromeric complexes, revealing common and specific interfaces between transcriptionally repressed and derepressed states. Further, the salt-bridges can be reconfigured to switch the affinity between homomeric and heteromeric complexes in an incremental manner. The complex structure combined with quantitative binding analyses would be essential for deciphering the PB1 interaction code underlying the transcriptional regulation of auxin signaling.
Determinants of PB1 Domain Interactions in Auxin Response Factor ARF5 and Repressor IAA17.,Kim Y, Park C, Cha S, Han M, Ryu KS, Suh JY J Mol Biol. 2020 Jun 26;432(14):4010-4022. doi: 10.1016/j.jmb.2020.04.007. Epub , 2020 Apr 17. PMID:32305460[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Hagen G, Guilfoyle T. Auxin-responsive gene expression: genes, promoters and regulatory factors. Plant Mol Biol. 2002 Jun-Jul;49(3-4):373-85. PMID:12036261
- ↑ Hardtke CS, Ckurshumova W, Vidaurre DP, Singh SA, Stamatiou G, Tiwari SB, Hagen G, Guilfoyle TJ, Berleth T. Overlapping and non-redundant functions of the Arabidopsis auxin response factors MONOPTEROS and NONPHOTOTROPIC HYPOCOTYL 4. Development. 2004 Mar;131(5):1089-100. PMID:14973283 doi:http://dx.doi.org/10.1242/dev.00925
- ↑ Vidaurre DP, Ploense S, Krogan NT, Berleth T. AMP1 and MP antagonistically regulate embryo and meristem development in Arabidopsis. Development. 2007 Jul;134(14):2561-7. Epub 2007 Jun 6. PMID:17553903 doi:http://dx.doi.org/10.1242/dev.006759
- ↑ Kim Y, Park C, Cha S, Han M, Ryu KS, Suh JY. Determinants of PB1 Domain Interactions in Auxin Response Factor ARF5 and Repressor IAA17. J Mol Biol. 2020 Jun 26;432(14):4010-4022. PMID:32305460 doi:10.1016/j.jmb.2020.04.007
