p300 Serine 89: A Critical Signaling Integrator and Its Effects on Intestinal Homeostasis and Repair

Area of Science:

• Molecular Biology
• Stem Cell Biology
• Cancer Research

Background:

• Differential coactivator usage by β-catenin, involving CBP and p300, is crucial for stem cell regulation.
• p300 serine 89 (S89) phosphorylation is critical for controlling β-catenin coactivator selection in stem/progenitor cells.
• This residue is a target for multiple kinase signaling cascades.

Purpose of the Study:

• To investigate the role of p300 S89 phosphorylation in signal integration.
• To generate and analyze p300 S89A knock-in mice to understand its in vivo function.
• To explore the impact of this modification on intestinal health, immunity, and cancer susceptibility.

Main Methods:

• Generation of p300 S89A knock-in mouse models.
• Induction of intestinal insult (colitis) to assess sensitivity.
• Analysis of cell-intrinsic and microbiome differences using genomic and proteomic techniques.
• Evaluation of immune responses and metabolic pathways.

Main Results:

• S89A mice exhibit extreme sensitivity to intestinal insult, leading to colitis.
• Significant differences observed in cell-intrinsic properties, microbiome composition, and immune responses in S89A mice.
• Genomic and proteomic analyses revealed altered pathways including lipid metabolism, oxidative stress, and mitochondrial function.
• The S89A modification impacts epithelial differentiation, metabolism, immune response, and microbiome colonization.

Conclusions:

• The p300 S89 residue acts as a critical signaling nexus.
• A single amino acid modification at S89 profoundly affects fundamental biological processes.
• This highlights the evolutionary importance of this region in p300 for vertebrate health and disease.