T:G mismatch-specific thymine-DNA glycosylase (TDG) as a coregulator of transcription interacts with SRC1 family members through a novel tyrosine repeat motif.
Gene activation involves protein complexes with diverse enzymatic activities, some of which are involved in chromatin modification. We have shown previously that the base excision repair enzyme thymine DNA glycosylase (TDG) acts as a potent coactivator for estrogen receptor-alpha. To further understand how TDG acts in this context, we studied its interaction with known coactivators of nuclear receptors. We find that TDG interacts in vitro and in vivo with the p160 coactivator SRC1, with the interaction being mediated by a previously undescribed motif encoding four equally spaced tyrosine residues in TDG, each tyrosine being separated by three amino acids. This is found to interact with two motifs in SRC1 also containing tyrosine residues separated by three amino acids. Site-directed mutagenesis shows that the tyrosines encoded in these motifs are critical for the interaction. The related p160 protein TIF2 does not interact with TDG and has the altered sequence, F-X-X-X-Y, at the equivalent positions relative to SRC1. Substitution of the phenylalanines to tyrosines is sufficient to bring about interaction of TIF2 with TDG. These findings highlight a new protein-protein interaction motif based on Y-X-X-X-Y and provide new insight into the interaction of diverse proteins in coactivator complexes.
Lucey
Marie J
MJ
Department of Oncology, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Chen
Dongsheng
D
Lopez-Garcia
Jorge
J
Hart
Stephen M
SM
Phoenix
Fladia
F
Al-Jehani
Rajai
R
Alao
John P
JP
White
Roger
R
Kindle
Karin B
KB
Losson
Régine
R
Chambon
Pierre
P
Parker
Malcolm G
MG
Schär
Primo
P
Heery
David M
DM
Buluwela
Lakjaya
L
Ali
Simak
S
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D051548:Histone Acetyltransferases; D006801:Humans; D008969:Molecular Sequence Data; D056920:Nuclear Receptor Coactivator 1; D020449:Repetitive Sequences, Amino Acid; D044502:Thymine DNA Glycosylase / Q000737:chemistry* / Q000378:metabolism*; D015534:Trans-Activators / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014443:Tyrosine / Q000032:analysis
D015534:Trans-Activators; D014157:Transcription Factors; D014443:Tyrosine; D051548:Histone Acetyltransferases; C538859:NCOA1 protein, human; D056920:Nuclear Receptor Coactivator 1; D044502:Thymine DNA Glycosylase