Covalent Targeting of Splicing in T Cells

Area of Science:

• Biochemistry
• Immunology
• Molecular Biology

Background:

• Targeting RNA splicing is a growing area for therapeutics, but chemical probes for splicing factors are limited.
• Interleukin 2-inducible T cell kinase (ITK) plays a role in T cell signaling and is a potential therapeutic target.

Approach:

• Developed and tested stereoisomeric acrylamide chemical probe EV96 and analogues targeting SF3B1, a core splicing factor.
• Investigated T cell state-dependent loss of ITK using mechanistic studies on protein turnover and mRNA pools.
• Employed activity-based protein profiling (ABPP) with electrophilic fragments to assess covalent ligandability of splicing factors in human T cells.

Key Points:

• EV96 selectively causes T cell state-dependent loss of ITK by targeting SF3B1.
• State-dependency is linked to differential protein turnover and alternative splicing-driven mRNA depletion.
• Demonstrated broad covalent ligandability of splicing factors and regulators in primary human T cells.

Conclusions:

• Chemical perturbation of splicing can induce immune state-dependent changes in protein expression.
• Splicing factors are broadly targetable with covalent chemistry, opening new therapeutic avenues.