PROSITE documentation PDOC51745
PB1 domain profile


The PB1 (Phox and Bem1) domain, comprising about 80 amino acid residues, is conserved among animals, fungi, amoebas, and plants. It functions as a protein binding module through PB1-mediated heterodimerization or homo-oligomerization [1,2,3,4]. The PB1 domain is found in several signaling proteins including:

  • Mammalian MEK5, a MAP kinase kinase implicated in epidermal growth factor- induced cell proliferation.
  • Mammalian Sequestosome-1 (Sqstm1) or p62/ZIP, a protein linking the zeta isoform of protein kinase C to RIP and/or potassium channels.
  • Mammalian neutrophil cytosol factor 4 (NCF-4) or p40(phox), a cytosolic factor of the superoxide-generating NADPH oxidase in phagocytes.
  • Mammalian neutrophil cytosol factor 2 (NCF-2) or p67(phox), an oxidase activator.
  • Yeast bud emergence protein 1 (Bem1), necessary for cell polarization during vegetative growth.
  • Yeast cell division control protein 24 (CDC24), a guanine nucleotide exchange factor (GEF) for the small GTPase CDC42.
  • Plant AUXIN RESPONSE FACTOR (ARF) transcription factor family, regulates gene expression in response to auxin.
  • Plant AUXIN/INDOLE 3-ACETIC ACID (Aux/IAA) repressor proteins, repress ARF transcription factors via direct interaction under low auxin concentrations.

The PB1 domains adopt an ubiquitin-like β-grasp fold, containing two α helices and a mixed five-stranded β sheet (see <PDB:1WMH>). The β-sheet has a convex surface, and α1 fits into the cavity formed by the sheet. PB1 domains may display an acidic surface (type I), a basic surface (tape II), or both surfaces (type I/II) on opposite faces of the domain structure to allow for front-to-back orientation of multiple PB1 domains [1,2,3,4].

The profile we developed covers the entire PB1 domain.

Last update:

January 2015 / First entry.


Technical section

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

PB1, PS51745; PB1 domain profile  (MATRIX)


1AuthorsSumimoto H. Kamakura S. Ito T.
TitleStructure and function of the PB1 domain, a protein interaction module conserved in animals, fungi, amoebas, and plants.
SourceSci. STKE 2007:Re6-Re6(2007).
PubMed ID17726178

2AuthorsHirano Y. Yoshinaga S. Takeya R. Suzuki N.N. Horiuchi M. Kohjima M. Sumimoto H. Inagaki F.
TitleStructure of a cell polarity regulator, a complex between atypical PKC and Par6 PB1 domains.
SourceJ. Biol. Chem. 280:9653-9661(2005).
PubMed ID15590654

3AuthorsTerasawa H. Noda Y. Ito T. Hatanaka H. Ichikawa S. Ogura K. Sumimoto H. Inagaki F.
TitleStructure and ligand recognition of the PB1 domain: a novel protein module binding to the PC motif.
SourceEMBO J. 20:3947-3956(2001).
PubMed ID11483498

4AuthorsKorasick D.A. Westfall C.S. Lee S.G. Nanao M.H. Dumas R. Hagen G. Guilfoyle T.J. Jez J.M. Strader L.C.
TitleMolecular basis for AUXIN RESPONSE FACTOR protein interaction and the control of auxin response repression.
SourceProc. Natl. Acad. Sci. U.S.A. 111:5427-5432(2014).
PubMed ID24706860

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