The adipogenic acetyltransferase Tip60 targets activation function 1 of peroxisome proliferator-activated receptor gamma.
The transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma) plays a key role in the regulation of lipid and glucose metabolism in adipocytes, by regulating their differentiation, maintenance, and function. The transcriptional activity of PPARgamma is dictated by the set of proteins with which this nuclear receptor interacts under specific conditions. Here we identify the HIV-1 Tat-interacting protein 60 (Tip60) as a novel positive regulator of PPARgamma transcriptional activity. Using tandem mass spectrometry, we found that PPARgamma and the acetyltransferase Tip60 interact in cells, and through use of chimeric proteins, we established that coactivation by Tip60 critically depends on the N-terminal activation function 1 of PPARgamma, a domain involved in isotype-specific gene expression and adipogenesis. Chromatin immunoprecipitation experiments showed that the endogenous Tip60 protein is recruited to PPARgamma target genes in mature 3T3-L1 adipocytes but not in preadipocytes, indicating that Tip60 requires PPARgamma for its recruitment to PPARgamma target genes. Importantly, we show that in common with disruption of PPARgamma function, small interfering RNA-mediated reduction of Tip60 protein impairs differentiation of 3T3-L1 preadipocytes. Taken together, these findings qualify the acetyltransferase Tip60 as a novel adipogenic factor.
van Beekum
Olivier
O
Department of Metabolic and Endocrine Diseases, University Medical Center Utrecht, Lundlaan 6, Utrecht, The Netherlands.
Brenkman
Arjan B
AB
Grøntved
Lars
L
Hamers
Nicole
N
van den Broek
Niels J F
NJ
Berger
Ruud
R
Mandrup
Susanne
S
Kalkhoven
Eric
E
D041721:3T3-L1 Cells; D050156:Adipogenesis; D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D051548:Histone Acetyltransferases / Q000502:physiology*; D006801:Humans; D000074443:Lysine Acetyltransferase 5; D051379:Mice; D008969:Molecular Sequence Data; D047495:PPAR gamma / Q000737:chemistry / Q000502:physiology*; D017434:Protein Structure, Tertiary; D014158:Transcription, Genetic
D047495:PPAR gamma; D051548:Histone Acetyltransferases; C098489:KAT5 protein, human; D000074443:Lysine Acetyltransferase 5