InterPro domain: IPR044579

This entry represents a group of plant transcription factors, including bHLH11 and bHLH121 from Arabidopsis. They belong to the members of clade IVb of bHLH transcription factors. bHLH121 can bind to the promoters of the FIT (a crucial regulator of Fe-deficiency response) and bHLH Ib genes. It interacts with bHLH105 (ILR3) transcription factors and its closest homologues to positively regulate the expression of FIT [ 1 , 2 ]. bHLH11 functions as a negative regulator of FIT-dependent Fe uptake and modulates Fe levels in Arabidopsis plants [ 3 ].

1. bHLH121 Functions as a Direct Link that Facilitates the Activation of FIT by bHLH IVc Transcription Factors for Maintaining Fe Homeostasis in Arabidopsis. Mol Plant 13, 634-649
2. The Transcription Factor bHLH121 Interacts with bHLH105 (ILR3) and Its Closest Homologs to Regulate Iron Homeostasis in Arabidopsis. Plant Cell 32, 508-524
3. The basic helix-loop-helix transcription factor, bHLH11 functions in the iron-uptake system in Arabidopsis thaliana. J Plant Res 132, 93-105