# Structural and Functional Studies of the Lipid Metabolizing Enzymes Phospholipase D and Lipin

> **NIH NIH R35** · STATE UNIVERSITY NEW YORK STONY BROOK · 2020 · $459,886

## Abstract

PROJECT SUMMARY: We are interested in understanding how lipid-metabolizing enzymes
function and are regulated at the molecular and structural level. Our current focus is on two
enzymes in phosphatidic acid (PA) metabolism: Lipin and phospholipase D (PLD). Lipins are
lipid phosphatases that dephosphorylate PA to generate diacylglycerol, which is the penultimate
step in triglyceride biosynthesis. Lipins regulate triglyceride biosynthesis, triglyceride catabolism,
fatty acid synthesis, and insulin sensitivity with implications to obesity, diabetes, and
cardiovascular disease. PLDs hydrolyze phosphatidylcholine to produce the lipid second
messenger PA in response to extracellular stimuli. Receptor-mediated activation of PLD
regulates vesicular trafficking, cell proliferation, and cell migration, which has established them
as therapeutic targets for cancer. Both Lipin and PLD are highly regulated, multi-domain
proteins that are structurally uncharacterized. Determining the three-dimensional structures of
these enzymes alone, and in complex with their lipid substrates, lipid activators, and protein
activators is essential to understanding their function and regulation. In preliminary data, we
have used innovative bioinformatics and protein engineering to identify endogenous homologs
and constructs of mouse/human Lipin and PLD that are more amenable for structural studies,
demonstrated these constructs are fully functional in cells and in vitro, and obtained diffraction
quality crystals. Structural studies will be complemented by an array of lipid biochemistry and
lipid-protein interaction assays that we are well versed in, hydrogen-deuterium exchange mass
spectrometry, and cellular studies in mammalian cells and yeast. A network of collaborators who
are leaders in their respective fields supports these studies. We aim to answer several major
questions: (1) How do lipid-modifying enzymes recognize their hydrophobic substrates and
interact with the membrane during interfacial catalysis? (2) What role do novel structurally and
functionally uncharacterized domains play in the action of these enzymes? (3) How do lipids
activate these enzymes? (4) How are these enzymes regulated? Specifically, are they
autoinhibited? How do protein effectors activate them? And what conformational changes occur
during activation? Overall, this work will improve our understanding of biological mechanisms
and provide information on lipid-protein interactions of physiological and pharmacological
significance. In addition, this work will aid our long-term interest to develop and improve small
molecule modulators of these enzymes, which would have potential therapeutic applications for
the treatment of cancer, cardiovascular disease, and diabetes.

## Key facts

- **NIH application ID:** 9982376
- **Project number:** 5R35GM128666-03
- **Recipient organization:** STATE UNIVERSITY NEW YORK STONY BROOK
- **Principal Investigator:** Michael Virgil Airola
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $459,886
- **Award type:** 5
- **Project period:** 2018-08-01 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9982376

## Citation

> US National Institutes of Health, RePORTER application 9982376, Structural and Functional Studies of the Lipid Metabolizing Enzymes Phospholipase D and Lipin (5R35GM128666-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9982376. Licensed CC0.

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