# Nanoscale organization and mechanotransduction of emerin at the nuclear envelope: Implication for Emery-Dreifuss Muscular Dystrophy

> **NIH NIH R21** · UNIVERSITY OF SOUTHERN CALIFORNIA · 2020 · $217,800

## Abstract

ABSTRACT
Emerin is an integral membrane protein of the inner nuclear envelope (INE) that binds to various nucleoskeletal partners
and is a critical actor for the maintenance of the nucleus architecture and for nuclear mechanotransductions in response to
forces. When mutated or absent, emerin causes Emery-Dreifuss muscular dystrophy (EDMD), an envelopathy whose
underlying mechanisms and muscle specific effects are not fully understood. In particular, how emerin participates in
molecular scaffolding at the INE and helps protect the nucleus against mechanical strains has remained largely elusive. As
we have shown recently, using state-of-the-art optical microscopy, this is because the spatial organization of emerin and its
mechanotransducing functions are modulated on distances of just a few nanometers at the INE, a length-scale inaccessible
by conventional microscopy imaging techniques. Defining the pathogenesis of EDMD and other envelopathies, therefore
demand new approaches that can establish the nanoscale structural organization of the INE while simultaneously modulating
the mechanical landscape of nuclei in intact cells. Here, we propose an innovative integration of super-resolution and single
molecule optical microscopy, nuclear biomechanics, biochemistry and quantitative biophysical analyses: (i) to establish the
structural organization and the mechanotransducing functions of emerin at the nanoscale in human cells and (ii) to uncover
the mechanisms by which its mutation results in abnormal nuclear mechanics in EDMD.
Building on a large set of preliminary data with mutated emerins that localize correctly to the NE but induce EDMD, we
hypothesize that the nanoscale oligomerization of emerin is directly coupled to its mechanotransducing functions and is
further regulated by competitive interactions with various nucleoskeletal niches. We also hypothesize that defective nuclear
biomechanics stem from dysregulated emerin oligomerization and, consequently, defective organization of structural niches
at the INE. These hypotheses will be tested in two aims. In Aim 1, we will determine how nucleoskeletal niches differentially
enriched in key emerin binding partners modulate the diffusion dynamics and the oligomeric state of wild-type emerin and
a variety of EDMD-inducing emerin mutants at the INE of rescued emerin-null cells from human EDMD patients. This will
be done using multi-parametric super-resolution microscopy, single molecule tracking and biochemical assays. In Aim 2,
we will define the functional roles of emerin as a key nuclear envelope mechanotransducer in the context of EDMD by
establishing how changes in the nanoscale distribution and oligomerization of wild-type emerin or emerin mutants dictate
the normal or pathogenic mechanical responses of cell nuclei to increasing forces. This will be achieved using cell
micropatterning approaches that controllably modulate the mechanical landscape of nuclei directly in cells.
Together, this research...

## Key facts

- **NIH application ID:** 9868653
- **Project number:** 1R21AR076514-01
- **Recipient organization:** UNIVERSITY OF SOUTHERN CALIFORNIA
- **Principal Investigator:** Fabien Pinaud
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $217,800
- **Award type:** 1
- **Project period:** 2020-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9868653

## Citation

> US National Institutes of Health, RePORTER application 9868653, Nanoscale organization and mechanotransduction of emerin at the nuclear envelope: Implication for Emery-Dreifuss Muscular Dystrophy (1R21AR076514-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9868653. Licensed CC0.

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