# Structural analysis of protein-protein and protein-lipid interactions of lens membrane proteins.

> **NIH NIH F31** · VANDERBILT UNIVERSITY · 2021 · $30,811

## Abstract

Summary/abstract: Cataract is the leading cause of blindness worldwide, costing the US Healthcare system
billions of dollars annually for surgical treatment. Lens opacification has been linked to dysfunction in major
membrane proteins, Aquaporin-0 (AQP0) and Lim2. The overall goal of my project is to develop a
comprehensive understanding of the structure and function of protein-protein and protein-lipid interactions of
these membrane proteins. In the absence of a blood supply, the microcirculation system transports nutrients
and removes wastes to inner fiber cells and is essential for maintaining lens transparency over decades of life;
however, how this microcirculation system is established and maintained as a function of age is not well
understood. Using advanced mass spectrometry techniques such as hydrogen-deuterium exchange-MS,
native-MS and chemical crosslinking studies, I intend to elucidate how specific protein and lipid interactions
impact the structure and function of AQP0 and Lim2; membrane proteins that are fundamental to the
microcirculation system of the lens. The most abundant lens membrane protein, AQP0, plays important roles in
lens fiber cell adhesion and water permeability with water permeability regulated by interaction with the
calcium-binding protein, calmodulin. Data from my lab and others demonstrated that calmodulin interacts with
the C-terminal tail of AQP0; however, molecular dynamic (MD) simulations suggest a non-canonical interaction
with a cytosolic loop of AQP0. This MD prediction has not been experimentally validated. In addition to AQP0-
protein interactions (Aim 1), I hypothesize that AQP0-lipid interactions (Aim 2) regulate AQP0 permeability and
adhesion properties that underlie lens transparency; however, there are limited reports on AQP0 interactions
with native lipids. Given the vital role of AQP0 in maintaining lens transparency and its connection to cataract,
understanding regulatory interactions with proteins such as calmodulin and native lipids will clarify its role in the
microcirculation system. The second most abundant membrane protein in the lens is Lim2 and, like AQP0, its
mutation has been associated with cataractogenesis in mice; however, little is known about Lim2-protein
interactions (Aim 1). Binding partners to Lim2 have been reported, i.e. calmodulin and galectin-3, but how
these interactions modulate Lim2 structure and function are not clear. Additionally, native lens lipids have been
reported to impact Lim2 subunit assembly, but the details underlying this phenomenon have not been
explored. As a result of the scarcity of experimental research on Lim2-native lipid interactions (Aim 2), I will use
native MS to identify specific lipid interactions and determine how they affect Lim2 structure. My findings will
aid researchers develop therapeutic targets and/or practices that can prevent, reverse or delay cataract
formation.

## Key facts

- **NIH application ID:** 10313202
- **Project number:** 1F31EY032348-01A1
- **Recipient organization:** VANDERBILT UNIVERSITY
- **Principal Investigator:** Carla O'Neale
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $30,811
- **Award type:** 1
- **Project period:** 2021-12-01 → 2023-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10313202

## Citation

> US National Institutes of Health, RePORTER application 10313202, Structural analysis of protein-protein and protein-lipid interactions of lens membrane proteins. (1F31EY032348-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10313202. Licensed CC0.

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