Structural insights into TAZ2 domain–mediated CBP/p300 recruitment by transactivation domain 1 of the lymphopoietic transcription factor E2A

• Published in: The Journal of biological chemistry Vol. 295; no. 13; pp. 4303 - 4315
• Main Authors: Lochhead, Marina R., Brown, Alexandra D., Kirlin, Alyssa C., Chitayat, Seth, Munro, Kim, Findlay, Jane E., Baillie, George S., LeBrun, David P., Langelaan, David N., Smith, Steven P.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 27.03.2020; American Society for Biochemistry and Molecular Biology
• Subjects: B-Lymphocytes - chemistry; B-Lymphocytes - metabolism; basic helix-loop-helix transcription factor (bHLH); CREB-Binding Protein - chemistry; CREB-Binding Protein - genetics; CREB-Binding Protein - ultrastructure; E1A-Associated p300 Protein - chemistry; E1A-Associated p300 Protein - genetics; E1A-Associated p300 Protein - ultrastructure; E1A-binding protein p300 (P300); hematopoiesis; Homeodomain Proteins - chemistry; Homeodomain Proteins - genetics; Homeodomain Proteins - ultrastructure; Humans; intrinsically disordered protein; isothermal titration calorimetry (ITC); lymphocyte; Mutation - genetics; nuclear magnetic resonance (NMR); Oncogene Proteins, Fusion - chemistry; Oncogene Proteins, Fusion - genetics; Oncogene Proteins, Fusion - ultrastructure; Protein Binding - genetics; Protein Conformation; Protein Domains - genetics; protein structure; Protein Structure and Folding; protein-protein interaction; TAZ2 domain; Transcription Factor 3 - chemistry; Transcription Factor 3 - genetics; Transcription Factor 3 - ultrastructure; protein structure; hematopoiesis; intrinsically disordered protein; E1A-binding protein p300 (P300); nuclear magnetic resonance (NMR); basic helix-loop-helix transcription factor (bHLH); protein-protein interaction; TAZ2 domain; isothermal titration calorimetry (ITC); lymphocyte
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.RA119.011078

The E-protein transcription factors guide immune cell differentiation, with E12 and E47 (hereafter called E2A) being essential for B-cell specification and maturation. E2A and the oncogenic chimera E2A-PBX1 contain three transactivation domains (ADs), with AD1 and AD2 having redundant, independent, and cooperative functions in a cell-dependent manner. AD1 and AD2 both mediate their functions by binding to the KIX domain of the histone acetyltransferase paralogues CREB-binding protein (CBP) and E1A-binding protein P300 (p300). This interaction is necessary for B-cell maturation and oncogenesis by E2A-PBX1 and occurs through conserved ΦXXΦΦ motifs (with Φ denoting a hydrophobic amino acid) in AD1 and AD2. However, disruption of this interaction via mutation of the KIX domain in CBP/p300 does not completely abrogate binding of E2A and E2A-PBX1. Here, we determined that E2A-AD1 and E2A-AD2 also interact with the TAZ2 domain of CBP/p300. Characterization of the TAZ2:E2A-AD1(1–37) complex indicated that E2A-AD1 adopts an α-helical structure and uses its ΦXXΦΦ motif to bind TAZ2. Whereas this region overlapped with the KIX recognition region, key KIX-interacting E2A-AD1 residues were exposed, suggesting that E2A-AD1 could simultaneously bind both the KIX and TAZ2 domains. However, we did not detect a ternary complex involving E2A-AD1, KIX, and TAZ2 and found that E2A containing both intact AD1 and AD2 is required to bind to CBP/p300. Our findings highlight the structural plasticity and promiscuity of E2A-AD1 and suggest that E2A binds both the TAZ2 and KIX domains of CBP/p300 through AD1 and AD2.