The CREB-binding protein (CBP) and its paralog p300 are master transcriptional coactivators that integrate numerous signaling pathways and play critical roles in cell proliferation, differentiation, apoptosis, and DNA repair. The biological functions of CBP and p300 are largely exerted through multiple transcription factor interaction domains as well as a histone acetyl transferase (HAT) domain. However, a structural model of how transcription factor complexes with CBP and p300 modulate coactivator function is lacking. A well-studied cellular partner of CBP and p300 is the tumor suppressor protein p53. Several studies suggest that upon DNA damage CBP/p300 is recruited by p53 to modify chromatin and aid in transcriptional activation of p53 target genes. It has been hypothesized that each of the four transcriptional activation domains of an active p53 tetramer bind to four separate domains of a single CBP/p300 molecule, resulting in increased avidity that further stabilizes the p53-CBP/p300 complex and enhances p53-mediated transcription. However, the influence of p53 binding on local and global conformational changes in CBP/p300 and its effect on histone acetyltransferase activity has yet to be defined. Using a combination of single particle electron microscopy, solution biophysical and biochemical methods, the goal of the proposed work is to develop a comprehensive structure-function model of CBP/p300 in p53-mediated transcriptional activation.

Public Health Relevance

The CREB-binding protein (CBP) and its paralog p300 are transcriptional coactivators that regulate the expression of genes by mediating interactions with a multitude of transcription factors. Both CBP and p300 bind to and mediate the transcriptional functions of the tumor suppressor protein p53. By taking a holistic approach, the present investigation seeks to provide the first atomic resolution structural and mechanistic insights into the principles governing the binary complex formation of the intact transcriptional activator p53 and the master transcriptional coactivator CBP/p300.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
1F31GM131631-01
Application #
9682989
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Brown, Patrick
Project Start
2019-01-01
Project End
2021-04-30
Budget Start
2019-01-01
Budget End
2019-12-31
Support Year
1
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Type
Organized Research Units
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109