# IPMK function in chromatin

> **NIH NIH R01** · VANDERBILT UNIVERSITY MEDICAL CENTER · 2020 · $374,000

## Abstract

Abstract:
 For the past two decades, several labs including John York, Susan Wente, Steve Shears, Adolfo
Saiardi and Solomon Synder have tried to elucidate how higher-order inositol phosphate 2nd messenger
signaling molecules (inositols) regulate transcription, mainly examining single transcriptional units in yeast by
genetic complementation/epistasis analyses. These studies focused on the completely conserved and
ubiquitous inositol phosphate multikinase (IPMK, ipk2), as this kinase sits at the nexus of several pathways
required for production of all higher inositols. IPMK activity is clearly required to rescue yeast phenotypes and
transcripts from individual elements, but how inositols achieved this regulation was undescribed, as the
chromatin effectors of inositols were unknown. In 2003, Erin O'Shea showed the kinase activity of IPMK
regulates nucleosome sliding in yeast, Carl Wu and another group showed inositols regulate ATP-dependent
chromatin remodelers Ino80 and Swi/Snf in vitro. However, inositol regulation of ATP-remodelers has not been
built upon in any cellular studies since, despite availability of genomic approaches to examine open chromatin.
 We discovered a completely different way IPMK could regulate transcription, by directly
phosphorylating a phospholipid while the lipid is bound in the hydrophobic cleft of a nuclear receptor. This
model threatened to explain why the chromatin targets of IPMK were difficult to identify - they might be lipid-
binding proteins, not inositol-binding proteins. This led us to attempt to identify other transcription factors
regulated similarly by IPMK using genomics, presented in this proposal. In our human cell models we see
IPMK is recruited to hundreds of transcriptional start sites, controlling transcript accumulation at those
promoters in a kinase-dependent manner. But to our great surprise, GSEA immediately suggested IPMK
primarily (but certainly not exclusively) regulates gene expression through histone deacetylases (HDACs).
HDACs are transcriptional repressors shown in a series of structural biology papers by John Schwabe's group
to require inositols, not lipids, for full activity in vitro. Indeed, histone acetylation increases upon IPMK loss,
occurring at specific subsets of transcriptional start sites that recruit IPMK. All these aspects of IPMK functions
in chromatin and at transcriptional start sites are novel.
 This proposal more deeply interrogates the new chromatin functions of IPMK described in our
preliminary data, taking advantage of new chemical-genetics and other mutants of IPMK we have developed.
Aim 1 identifies which of the new chromatin events are mediated most directly by IPMK, so mechanism can be
studied. Aim 2 determines which IPMK-mediated chromatin events are shared between physiologically
relevant model systems. Aim 3 resolves the mechanism of IPMK gene regulation. This proposal addresses
long standing questions of how IPMK regulates gene expression while introducing a n...

## Key facts

- **NIH application ID:** 9973484
- **Project number:** 1R01GM132592-01A1
- **Recipient organization:** VANDERBILT UNIVERSITY MEDICAL CENTER
- **Principal Investigator:** Raymond Daniel Blind
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $374,000
- **Award type:** 1
- **Project period:** 2020-04-15 → 2024-02-29

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9973484

## Citation

> US National Institutes of Health, RePORTER application 9973484, IPMK function in chromatin (1R01GM132592-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9973484. Licensed CC0.

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