# Lipid droplet regulation and proteome dynamics

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA BERKELEY · 2024 · $299,110

## Abstract

PROJECT SUMMARY / ABSTRACT
Lipid droplets (LDs) are neutral lipid storage organelles that act as cellular hubs of lipid homeostasis.
Dysregulation in LD function has been implicated in prevalent metabolic diseases such as obesity, diabetes,
cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD). Indeed, the pathological hallmark of
NAFLD is the accumulation of large hepatic LDs. In addition to metabolic diseases, LDs have also been
implicated in cancer proliferation and survival, host-pathogen interactions, and neurodegeneration. Thus,
understanding how LDs are regulated has the potential to broadly impact our understanding of human health
and disease. LDs are ER-derived organelles that have a unique ultrastructure, consisting of a core of neutral
lipid surrounded by a phospholipid monolayer decorated with integral and peripheral proteins. While recent
findings have advanced our understanding of LD biogenesis, how LDs are regulated under different metabolic
conditions and how the composition of the LD proteome remain poorly understood. To overcome these critical
gaps in knowledge and define the mechanisms that regulate neutral lipid storage, we performed a series of
CRISPR-Cas9 screen in human cells using a fluorescence-based neutral lipid reporter under different metabolic
conditions. We also employed genetic screens to examine the mechanisms that regulate PLIN2, a near
ubiquitous Class II LD protein that plays important roles in regulating LD stability. Our findings establish a
compendium of neutral lipid storage regulators, revealing interesting novel regulators that are condition specific.
Furthermore, we identify several ubiquitination factors that influence neutral lipid storage and the stability of
PLIN2. The current proposal aims to build on the foundation provided by our extensive preliminary data to
characterize new mechanisms of LD regulation. In aim 1, we will complete our validation experiments to establish
an extensive, phenotypic-rich resource for the community that is hypothesis generating. We will also examine
the concept that metabolic state-dependent regulation of LDs is a significant contributor to cellular lipid
homeostasis. Finally, we will characterize high priority candidates in iPSC-derived hepatocytes and examine the
hypothesis that a subset of regulators governs LD stability as part of a host response to pathogens. In Aim 2, we
will define the role of new ubiquitination pathways in regulating lipid homeostasis, examining the hypothesis that
the identified factors regulate LD stability by controlling the degradation of PLIN2 during lipolysis. These findings
will provide new global and mechanistic insights in to LD proteome remodeling and regulation under different
metabolic conditions.

## Key facts

- **NIH application ID:** 10889133
- **Project number:** 5R01DK128099-04
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** JAMES A OLZMANN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $299,110
- **Award type:** 5
- **Project period:** 2021-09-30 → 2026-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10889133

## Citation

> US National Institutes of Health, RePORTER application 10889133, Lipid droplet regulation and proteome dynamics (5R01DK128099-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10889133. Licensed CC0.

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