Proteogenomics Reveals Microproteins in Activated T Cells

Area of Science:

• Proteomics
• Immunology
• Molecular Biology

Background:

• Noncanonical microproteins, encoded by small open reading frames (sORFs), play vital roles in biological processes.
• T cell activation is critical for adaptive immunity, but the role of novel microproteins in this process remains largely unknown.

Purpose of the Study:

• To identify and characterize novel microproteins in primary human T cells.
• To investigate the role of these microproteins in T cell activation.

Main Methods:

• Combined nascent proteomics and quantitative proteomics to identify microproteins in human T cells.
• Activated T cells using distinct methods (PMA/Ionomycin and CD3/CD28 antibodies) to analyze protein expression profiles.
• Experimental validation and bioinformatic analyses were performed on identified microproteins.

Main Results:

• Identified 411 novel microproteins, including 83 nascent microproteins, in primary human T cells.
• Characterized canonical and microprotein profiles under different T cell activation conditions.
• Discovered three functional microproteins (T1, T2, T3) regulating T cell activation, with T1 identified as a negative feedback regulator.

Conclusions:

• Developed an integrated approach for uncovering and elucidating novel microproteins.
• Highlighted the significant role of microproteins in regulating T cell activation and adaptive immunity.