Platelet α-granule cargo packaging and release are affected by the luminal proteoglycan, serglycin.

Background: Serglycin (SRGN) is an intragranular, sulfated proteoglycan in hematopoietic cells that affects granule composition and function.

Objective: To understand how SRGN affects platelet granule packaging, cargo release, and extra-platelet microenvironments.

Methods: Platelets and megakaryocytes from SRGN mice were assayed for secretion kinetics, cargo levels, granule morphology upon activation, and receptor shedding.