Multimerin Processing by Cells With and Without Pathways for Regulated Protein Secretion

Abstract Multimerin is a massive, soluble, homomultimeric, factor V-binding protein found in platelet -granules and in vascular endothelium. Unlike platelets, endothelial cells contain multimerin within granules that lack the secretory granule membrane protein P-selectin, and in culture, they constitutively secrete most of their synthesized multimerin. To further evaluate multimerin’s posttranslational processing and storage, …