# The role of the free energy landscape in Parkin's function and dysfunction in health and disease

> **NIH NIH R01** · TEXAS A&M AGRILIFE RESEARCH · 2021 · $340,811

## Abstract

The RING ubiquitin E3 ligases are a superfamily of proteins critical to protein homeostasis and signaling in
eukaryotes. Dysfunctions in E3 ligases are implicated in innumerable human diseases. This proposal focuses
on the regulation of the ubiquitin E3 ligase Parkin. Parkin is central to the controlled destruction of
damaged mitochondria by autophagy (mitophagy). Controlled mitophagy is particularly essential to cardiac
and neuronal health. Uncontrolled mitophagy due to mutations in Parkin is clearly a driver of early onset
Parkinson's disease (eoPD). Parkin is now implicated in a number of other neurological diseases,
cardiomyopathy and in various cancers. The central goal here is to create an understanding the physical
basis for regulation of Parkin and how clinically observed mutations promote unregulated activity leading to
inadequately controlled mitophagy and other biological defects.
Though much is known about the biology and structural basis of Parkin function, very little is certain about
the physical basis for its regulation. Parkin activity is suppressed by its intra-molecular association with a
ubiquitin-like domain and is allosterically activated by the binding of phosphorylated ubiquitin (pUb).
Phosphorlyation of the Ubl domain also promotes activation. This complicated intersection of regulatory
mechanisms can only be understood by the rigorous dissection of the underlying thermodynamics. Without
this knowledge one cannot fully interpret the effects of mutations that lead to disease.
We shall take advantage of the broad foundation of knowledge of the biology of Parkin and structural basis
of its function to address the poorly understood thermodynamics of allosteric regulation of Parkin. The basis
for regulatory control of Parkin will be cast in a modern statistical thermodynamics description of the
protein ensemble. The influence of allosteric regulators and post-translational modifications will be
examined by comprehensive hydrogen exchange monitored by mass spectrometry and NMR spectroscopy;
advanced NMR relaxation techniques; single molecule fluorescence; calorimetry; enzymology; and
mutagenesis.
A more rigorous and complete understanding of the regulation of Parkin will enable a robust interpretation
of pathological mutations. Not all pathological mutations can be simply explained as mutations that disrupt
the levels of protein or mutations that directly impact the catalytic site. Examples of common pathological
mutations will be examined to reveal the basis for their effects on Parkin's regulatory fidelity, with a longer-
range goal of determining how this impact might be mitigated by small molecule intervention.

## Key facts

- **NIH application ID:** 10102255
- **Project number:** 5R01GM129076-02
- **Recipient organization:** TEXAS A&M AGRILIFE RESEARCH
- **Principal Investigator:** A. JOSHUA WAND
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $340,811
- **Award type:** 5
- **Project period:** 2020-03-01 → 2024-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10102255

## Citation

> US National Institutes of Health, RePORTER application 10102255, The role of the free energy landscape in Parkin's function and dysfunction in health and disease (5R01GM129076-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10102255. Licensed CC0.

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