DNA binding protein phosphatase (DBP) is a highly conserved plant motif involved in sequence-specific DNA binding. This is not the same as DBB family in PlnTFDb which stands for Double B box - which is Group 1 of the C2C2-CO-like family.  These factors all have a PP2C (protein phosphatase 2C class) C-terminal catalytic domain (PF00481) and sequence alignment of the N-terminal region of the identified DBP-like factors describes the existence of a conserved domain, comprising a motif almost invariant in all the aligned sequences from all angiosperms, characterized by an N-terminal core F(L,V)PX(L,V,I)RSGXWSD DNA-binding motif (DNC). Sequences within the very N-terminus are more divergent, but do keep significant similarity within taxa, and might confer functional specificity. The phosphatase activity of these transcription factors enables cells to rapidly and reversibly modulate transcription factor function in response to signaling stimuli (Carrasco et al., 2005. PMID:15710688).

Carrasco et al., 2006, (PMID: 16762921) identified the tobacco 14-3-3 isoform G as a protein that interacts with a DBP factor. 14-3-3 recognition involves the N-terminal region of DBP1, which also supports the DNA binding activity attributed to DBP1.  They also showed that in planta 14-3-3 isoform G is directly involved in regulating DBP1 function by promoting nuclear export and subsequent cytoplasmic retention of DBP1 under conditions that in turn alleviate DBP1-mediated repression of target gene expression.  In Arabidopsis the AtDBP1 protein promotes flowering by regulating the transcript levels of several important integrators and floral meristem identity genes, including FLC, CO, SOC1, LFY, FT and FD. (Zhai et al., 2016, PMID: 26586176).  In maize there are at least 4 DBP family members but their role as transcription factors has not been investigated (Wei et al., 2014).

Last updated June 2023 by John Gray

References:

Carrasco JL, Ancillo G, Castelló MJ, Vera P. A novel DNA-binding motif, hallmark of a new family of plant transcription factors. Plant Physiol. 2005 Feb;137(2):602-6. doi: 10.1104/pp.104.056002. PMID: 15710688; PMCID: PMC1065360.

Carrasco JL, Castelló MJ, Vera P. 14-3-3 mediates transcriptional regulation by modulating nucleocytoplasmic shuttling of tobacco DNA-binding protein phosphatase-1. J Biol Chem. 2006 Aug 11;281(32):22875-81. doi: 10.1074/jbc.M512611200. Epub 2006 Jun 8. PMID: 16762921.

Zhai H, Ning W, Wu H, Zhang X, Lü S, Xia Z. DNA-binding protein phosphatase AtDBP1 acts as a promoter of flowering in Arabidopsis. Planta. 2016 Mar;243(3):623-33. doi: 10.1007/s00425-015-2433-y. Epub 2015 Nov 19. PMID: 26586176.

Wei K, Pan S. Maize protein phosphatase gene family: identification and molecular characterization. BMC Genomics. 2014 Sep 9;15(1):773. doi: 10.1186/1471-2164-15-773. PMID: 25199535; PMCID: PMC4169795.