PROSITE documentation PDOC51477
PAH domain profile


The paired amphipathic helix (PAH) domain is a protein-protein interaction domain present in eukaryotic proteins implied in transcription down-regulation, such as the SIN3 family of proteins. This domain occurs generally in repeats at the N-terminus of the protein containing it [1]. Sin3a is the central component of a transcriptional co-repressor complex that comprises the histone deacetylase (HDAC) 1 and 2. The three PAH domains of Sin3a associate with numerous DNA-binding proteins enabling the recruitment of the Sin3 complex to chromatin. PAH1 is known to interact so far with Opi1, Pf1, NRSF, N-CoR and SMRT while PAH2 interacts with a broader range of proteins including Mad protein family members, Sp1-like repressor proteins, HBP1, Pf1 and yeast Ume6 [2,3].

The 3D structure of the PAH domain has been determined. The PAH domain folds into a left-handed, four-helix bundle structure (see <PDB:2RMS> and <PDB:1G1E>). The amino acids in each of the helices and in the turn regions are arranged in such a way as to form a hydrophic cleft that constitutes the main surface of interaction with the Sin3 interaction domain (SID) amphipathic helix of transcription inhibitors such as SAP25 or Mad1 [1,4].

The profile we developed covers the entire PAH domain.

Last update:

February 2010 / First entry.


Technical section

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

PAH, PS51477; PAH domain profile  (MATRIX)


1AuthorsSahu S.C. Swanson K.A. Kang R.S. Huang K. Brubaker K. Ratcliff K. Radhakrishnan I.
TitleConserved themes in target recognition by the PAH1 and PAH2 domains of the Sin3 transcriptional corepressor.
SourceJ. Mol. Biol. 375:1444-1456(2008).
PubMed ID18089292

2AuthorsLe Guezennec X. Vermeulen M. Stunnenberg H.G.
TitleMolecular characterization of Sin3 PAH-domain interactor specificity and identification of PAH partners.
SourceNucleic Acids Res. 34:3929-3937(2006).
PubMed ID16914451

3AuthorsSpronk C.A. Tessari M. Kaan A.M. Jansen J.F. Vermeulen M. Stunnenberg H.G. Vuister G.W.
TitleThe Mad1-Sin3B interaction involves a novel helical fold.
SourceNat. Struct. Biol. 7:1100-1104(2000).
PubMed ID11101889

4AuthorsBrubaker K. Cowley S.M. Huang K. Loo L. Yochum G.S. Ayer D.E. Eisenman R.N. Radhakrishnan I.
TitleSolution structure of the interacting domains of the Mad-Sin3 complex: implications for recruitment of a chromatin-modifying complex.
SourceCell 103:655-665(2000).
PubMed ID11106735

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