MLKL activity requires a splicing-regulated, druggable intramolecular interaction

Area of Science:

• Molecular Biology
• Cell Death Research
• Immunology

Background:

• Necroptosis is an inflammatory cell death pathway implicated in various human diseases.
• The pseudokinase mixed lineage kinase domain-like (MLKL) protein is crucial for executing necroptosis.
• The precise mechanisms regulating MLKL activity remain incompletely understood.

Purpose of the Study:

• To investigate the role of alternative splicing in MLKL function.
• To identify novel therapeutic targets for necroptosis-driven pathologies.
• To explore the structural basis of MLKL activation.

Main Methods:

• Analysis of MLKL splicing variants and their impact on cell death.
• Structural studies to identify MLKL interaction sites.
• Development and testing of small molecule inhibitors targeting MLKL.
• In vivo studies using murine models of inflammatory diseases.

Main Results:

• A splicing-dependent insertion in MLKL's C-terminal helix creates an anti-necroptotic isoform.
• Interaction with a novel hydrophobic groove on MLKL is essential for necroptosis.
• Small molecules inhibiting MLKL ameliorated disease in mouse models of dermatitis and aortic aneurysm.
• Alternative splicing regulates MLKL's intramolecular rearrangement critical for necroptosis.

Conclusions:

• Alternative splicing of microexons provides a regulatory mechanism for MLKL-mediated necroptosis.
• Targeting the MLKL hydrophobic groove offers a promising strategy for developing allosteric inhibitors.
• This research paves the way for new treatments for diseases involving necroptosis.