P160/SRC/NCoA coactivators form complexes via specific interaction of their PAS-B domain with the CID/AD1 domain.
Transcriptional activation involves the ordered recruitment of coactivators via direct interactions between distinct binding domains and recognition motifs. The p160/SRC/NCoA coactivator family comprises three members (NCoA-1, -2 and -3), which are organized in multiprotein coactivator complexes. We had identified the PAS-B domain of NCoA-1 as an LXXLL motif binding domain. Here we show that NCoA family members are able to interact with other full-length NCoA proteins via their PAS-B domain and they specifically interact with the CBP-interaction domain (CID/AD1) of NCoA-1. Peptide competition, binding experiments and mutagenesis of LXXLL motifs point at distinct binding motif specificities of the NCoA PAS-B domains. NMR studies of different NCoA-1-PAS-B/LXXLL peptide complexes revealed similar although not identical binding sites for the CID/AD1 and STAT6 transactivation domain LXXLL motifs. In mechanistic studies, we found that overexpression of the PAS-B domain is able to disturb the binding of NCoA-1 to CBP in cells and that a CID/AD1 peptide competes with STAT6 for NCoA-1 in vitro. Moreover, the expression of an endogenous androgen receptor target gene is affected by the overexpression of the NCoA-1 or NCoA-3 PAS-B domains. Our study discloses a new, complementary mechanism for the current model of coactivator recruitment to target gene promoters.
Lodrini
Marco
M
Georg-Speyer-Haus, Institute for Biomedical Research, Paul-Ehrlich-Strasse 42-44, 60596 Frankfurt, Germany.
Münz
Tobias
T
Coudevylle
Nicolas
N
Griesinger
Christian
C
Becker
Stefan
S
Pfitzner
Edith
E
D020816:Amino Acid Motifs; D001667:Binding, Competitive; D050882:CREB-Binding Protein / Q000378:metabolism; D002460:Cell Line; D051548:Histone Acetyltransferases / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D056920:Nuclear Receptor Coactivator 1; D051958:Nuclear Receptor Coactivator 2 / Q000737:chemistry* / Q000378:metabolism; D056921:Nuclear Receptor Coactivator 3; D054730:Protein Interaction Domains and Motifs; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D050800:STAT6 Transcription Factor / Q000378:metabolism; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D015533:Transcriptional Activation
D051958:Nuclear Receptor Coactivator 2; D018160:Receptors, Cytoplasmic and Nuclear; D050800:STAT6 Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors; D050882:CREB-Binding Protein; D051548:Histone Acetyltransferases; C538859:NCOA1 protein, human; C538866:NCOA3 protein, human; D056920:Nuclear Receptor Coactivator 1; D056921:Nuclear Receptor Coactivator 3