PROSITE documentation PDOC51978
PBC domain profile


The homeobox transcription factors (TFs) are ubiquitous in eukaryotes, carrying a DNA-binding homeodomain typically 60 amino acids that folds into three α-helices. Homeodomain proteins are classified into different classes based on the sequence of the homeodomain itself, as well as on the basis of additional conserved domains found in these proteins. The atypical or TALE (three-amino acid length extension) superclass of homeobox TFs shares a three-amino-acid insertion between helix 1 and 2 and plays essential roles during embryonic development by participating in interactive TF networks. The heterodimerization of TALE proteins serves as a trigger for precise execution of developmental programs. TALE-heterodimerization is mediated by class-specific homology domains located on the N-terminal side adjacent to the homeodomain. The PBC class of TALE homeodomain proteins includes the products of the vertebrate Pbx1, Pbx2, Pbx3 and Pbx4, Caenorhabditis elegans ceh-20, ceh-40 and ceh-60 and the Drosophila extradenticle (exd) genes. The sequence similarity between the PBC proteins extends downstream of the homeodomain for about 15 amino acids, and upstream of the homeodomain is a 180-amino acid domain termed PBC. The PBC domain can be further subdivided into an A and B region [1,2,3,4,5,6,7,8].

The profile we developed covers the entire PBC domain.

Last update:

June 2021 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

PBC, PS51978; PBC domain profile  (MATRIX)


1AuthorsBuerglin T.R. Ruvkun G.
TitleNew motif in PBX genes.
SourceNat. Genet. 1:319-320(1992).
PubMed ID1363814

2AuthorsBuerglin T.R.
TitleAnalysis of TALE superclass homeobox genes (MEIS, PBC, KNOX, Iroquois, TGIF) reveals a novel domain conserved between plants and animals.
SourceNucleic. Acids. Res. 25:4173-4180(1997).

3AuthorsBuerglin T.R.
TitleThe PBC domain contains a MEINOX domain: coevolution of Hox and TALE homeobox genes?
SourceDev. Genes. Evol. 208:113-116(1998).
PubMed ID9336443

4AuthorsBerthelsen J. Kilstrup-Nielsen C. Blasi F. Mavilio F. Zappavigna V.
TitleThe subcellular localization of PBX1 and EXD proteins depends on nuclear import and export signals and is modulated by association with PREP1 and HTH.
SourceGenes. Dev. 13:946-953(1999).
PubMed ID10215622

5AuthorsKilstrup-Nielsen C. Alessio M. Zappavigna V.
TitlePBX1 nuclear export is regulated independently of PBX-MEINOX interaction by PKA phosphorylation of the PBC-B domain.
SourceEMBO. J. 22:89-99(2003).
PubMed ID12505987

6AuthorsMukherjee K. Buerglin T.R.
TitleComprehensive analysis of animal TALE homeobox genes: new conserved motifs and cases of accelerated evolution.
SourceJ. Mol. Evol. 65:137-153(2007).
PubMed ID17665086

7AuthorsBuerglin T.R. Affolter M.
TitleHomeodomain proteins: an update.
SourceChromosoma 125:497-521(2016).
PubMed ID26464018

8AuthorsJoo S. Wang M.H. Lui G. Lee J. Barnas A. Kim E. Sudek S. Worden A.Z. Lee J.-H.
TitleCommon ancestry of heterodimerizing TALE homeobox transcription factors across Metazoa and Archaeplastida.
SourceBMC Biol. 16:136-136(2018).
PubMed ID30396330

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