AP2

DNA-binding domain in plant proteins such as APETALA2 and EREBPs
AP2
SMART accession number:SM00380
Description:
Interpro abstract (IPR001471):

Ethylene is an endogenous plant hormone that influences many aspects of plant growth and development. Some defense related genes that are induced by ethylene contain a cis-regulatory element known as the Ethylene- Responsive Element (ERE) [(PUBMED:2535512)]. Sequence analysis on various ERE regions has identified a short motif rich in G/C nucleotides, the GCC-box, essential for the response to ethylene. This short motif is recognised by a family of transcrition factors, the ERE binding factors (ERF) [(PUBMED:10715325)].

ERF proteins contain a domain of around 60 amino acids which is also found in the APETALA2 (AP2) protein [(PUBMED:7773013)]. This AP2/ERF domain has been shown in various proteins to be necessary and sufficient to bind the GCC-box [(PUBMED:9756931)].

The structure of the AP2/ERF domain in complex with the target DNA has been solved [(PUBMED:9736626)]. The structure resembles that of bacteriophage integrases and the methyl-CpG-binding domain (MBD): a three-stranded beta-sheet and an alpha helix almost parallel to the beta-sheet. It contacts DNA via Arg and Trp residues located in the beta- sheet.

Some proteins known to contain an AP2/ERF domain include:

  • Arabidopsis thaliana ERF1 to 6.
  • Tobacco ethylene-responsive element-binding proteins (EREBPs), homologues of ERF proteins.
  • Arabidopsis thaliana AP2 protein. It regulates meristeme identity, floral organ specification and seed coat development.
  • Arabidopsis thaliana C-repeat/dehydration-responsive element (DRE) binding factor 1 (CBF1 or DREB1) and DREB2. They bind a GCC-box-like element found in dehydratation responsive element. Binding to this element mediates cold-inducible transcription.
  • Arabidopsis thaliana and maize abscisic acid (ABA)-insensitive 4 (ABI4) proteins. They bind to a GCC-box-like element found in ABA-responsive genes.
  • Octadecanoid-derivative responsive catharenthus AP2-domain (ORCA2) protein. It binds a GCC-box-like element in the jasmonate responsive element of Str promoter.
  • Tomato Pto-interacting proteins 4 to 6 (Pti4 to Pti6). Pti5 and 6 bind a GCC-box-like element in regulatory regions of various pathogenesis-related (PR) genes.
  • Trichodesmium erythraeum, Tetrahymena thermophila, Enterobacteria phage RB49 and bacteriophage Felix 01 HNH endonucleases. HNH endonucleases are homing endonucleases that move extensively via lateral gene transfer [(PUBMED:15319480)].

This entry represents the AP2/ERF domain.

GO process:regulation of transcription, DNA-dependent (GO:0006355)
GO function:sequence-specific DNA binding transcription factor activity (GO:0003700)
Family alignment:
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There are 2510 AP2 domains in 2228 proteins in SMART's nrdb database.

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