Catalytic proteasome subunits are heterogeneously active in human platelets with β1i playing a role in signaling and granule release

Abstract

• •
  Human platelets contain catalytically active subunits of both constitutive and immunoproteasomes, with predominant expression of β5i, β5c, β1i, and β1c subunits.
• •
  Analysis of 31 healthy donors revealed substantial interindividual variability in both the protein levels and active states of proteasome subunits in platelets.
• •
  The proteasome catalytic subunit β1i was found to play a significant role in regulating platelet signaling pathways, particularly influencing the p38 and NFкB pathway.
• •
  Inhibition of β1i enhanced α-granule release, notably increasing CCL5 secretion, upon ADP activation, highlighting its potential role in platelet activation and immune regulation.