NEDD4L intramolecular interactions regulate its auto and substrate Na_V1.5 ubiquitination

Area of Science:

• Biochemistry
• Molecular Biology
• Cardiology

Background:

• NEDD4-like (NEDD4L) is a HECT-type E3 ligase regulating intracellular substrates.
• NEDD4L's enzymatic activity, crucial for proteostasis, is controlled by intramolecular interactions.
• Dysregulation of cardiac sodium channel NaV1.5 is linked to heart failure and arrhythmias.

Purpose of the Study:

• To investigate the autoregulatory mechanisms of NEDD4L.
• To elucidate the role of NEDD4L in NaV1.5 ubiquitination and function.
• To develop novel modulators of NaV1.5 activity.

Main Methods:

• Extensive biochemical and functional analyses.
• In vitro and electrophysiological experiments.
• Design of a genetically encoded NaV1.5 modulator.

Main Results:

• The C2 domain and the first WW-linker (1,2-linker) are implicated in NEDD4L autoregulation.
• The NEDD4L 1,2-linker is crucial for NaV1.5 substrate ubiquitination.
• NEDD4L preferentially ubiquitinates the DI-DII linker of NaV1.5 at the 2,3-linker sites.
• A nanobody-based modulator reduced Na+ current by targeting the NEDD4L HECT domain.

Conclusions:

• This study clarifies NEDD4L regulatory mechanisms and NaV1.5 ubiquitination.
• Findings provide a molecular framework for understanding NaV1.5 regulation in cardiac physiology and disease.
• A novel nanobody-based approach offers potential therapeutic strategies for cardiac channelopathies.