Structural basis of CBP/p300 recruitment by the microphthalmia-associated transcription factor

Alexandra D Brown; Kathleen L Vergunst; Makenzie Branch; Connor M Blair; Denis J Dupré; George S Baillie; David N Langelaan

doi:10.1016/j.bbamcr.2023.119520

Structural basis of CBP/p300 recruitment by the microphthalmia-associated transcription factor

Biochim Biophys Acta Mol Cell Res. 2023 Oct;1870(7):119520. doi: 10.1016/j.bbamcr.2023.119520. Epub 2023 Jun 21.

Authors

Alexandra D Brown¹, Kathleen L Vergunst¹, Makenzie Branch¹, Connor M Blair², Denis J Dupré³, George S Baillie², David N Langelaan⁴

Affiliations

¹ Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
² School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom of Great Britain and Northern Ireland.
³ Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
⁴ Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada. Electronic address: david.langelaan@dal.ca.

PMID: 37353163
DOI: 10.1016/j.bbamcr.2023.119520

Abstract

The microphthalmia-associated transcription factor (MITF) is a master regulator of the melanocyte cell lineage. Aberrant MITF activity can lead to multiple malignancies including skin cancer, where it modulates the progression and invasiveness of melanoma. MITF-regulated gene expression requires recruitment of the transcriptional co-regulator CBP/p300, but details of this process are not fully defined. In this study, we investigate the structural and functional interaction between the MITF N-terminal transactivation domain (MITF_TAD) and CBP/p300. Using pulldown assays and nuclear magnetic resonance spectroscopy we determined that MITF_TAD is intrinsically disordered and binds to the TAZ1 and TAZ2 domains of CBP/p300 with moderate affinity. The solution-state structure of the MITF_TAD:TAZ2 complex reveals that MITF interacts with a hydrophobic surface of TAZ2, while remaining somewhat dynamic. Peptide array and mutagenesis experiments determined that an acidic motif is integral to the MITF_TAD:TAZ2 interaction and is necessary for transcriptional activity of MITF. Peptides that bind to the same surface of TAZ2 as MITF_TAD, such as the adenoviral protein E1A, are capable of displacing MITF from TAZ2 and inhibiting transactivation. These findings provide insight into co-activator recruitment by MITF that are fundamental to our understanding of MITF targeted gene regulation and melanoma biology.

Keywords: CBP/p300; MITF; NMR spectroscopy; Protein complex; Protein structure and function; Transactivation domain.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Humans
Melanoma* / genetics
Melanoma* / pathology
Microphthalmia-Associated Transcription Factor* / genetics
Protein Structure, Tertiary

Substances

Microphthalmia-Associated Transcription Factor