Human histone acetyltransferase GCN5 exists in a stable macromolecular complex lacking the adapter ADA2.
Acetylation of core histones is an important regulatory step in transcriptional activation from chromatin templates. The yeast transcriptional coactivator protein GCN5 was recently shown to be a nuclear histone acetyltransferase (HAT). Genetic and biochemical studies in yeast suggest that GCN5 functions with the adapter proteins ADA1, ADA2, ADA3, and ADA5 in a heteromeric complex. We have established conditions for chromatographic fractionation of HATs and ADA2 from human K562 erythroleukemia cells. Gel-filtration chromatography revealed two populations of GCN5 with Stokes' radii of 67 and 33 A, consistent with a large macromolecular complex and a monomer, respectively. The GCN5-related HAT, PCAF, was resolved as a stable complex with a Stokes' radius of 74 A. The HAT complexes were resistant to 0.3 M NaCl and DNase I. ADA2 was characterized by a Stokes' radius of 35 A, consistent with a monomer. Thus, in contrast to the stable GCN5-adapter complex in yeast, human GCN5 and ADA2 are not stably associated with each other. The implications of this result are discussed vis-a-vis the mechanism of recruitment of GCN5 to regulatory regions of genes.
Forsberg
E C
EC
Department of Pharmacology, University of Wisconsin Medical School, 387 Medical Science Building, 1300 University Avenue, Madison, Wisconsin 53706, USA.
Lam
L T
LT
Yang
X J
XJ
Nakatani
Y
Y
Bresnick
E H
EH
D000123:Acetyltransferases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D015153:Blotting, Western; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000737:chemistry; D002843:Chromatin / Q000737:chemistry; D002850:Chromatography, Gel; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins; D003850:Deoxyribonuclease I / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism; D006367:HeLa Cells / Q000737:chemistry; D051548:Histone Acetyltransferases; D006801:Humans; D019901:Locus Control Region / Q000235:genetics; D008958:Models, Molecular; D011487:Protein Conformation; D012045:Regulatory Sequences, Nucleic Acid; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
D000123:Acetyltransferases; D048868:Adaptor Proteins, Signal Transducing; D018797:Cell Cycle Proteins; D002843:Chromatin; D004247:DNA; D004268:DNA-Binding Proteins; D003850:Deoxyribonuclease I; D005656:Fungal Proteins; D051548:Histone Acetyltransferases; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C097695:TADA2A protein, human; C501179:KAT2A protein, human