Human Beclin 1 Synthetic Peptide. Beclin 1 plays a central role in autophagy. It acts as a core subunit of the PI3K complex that mediates formation of phosphatidylinositol 3-phosphate. Different PI3K complex forms are believed to play a role in multiple membrane trafficking pathways - PI3KC3-C1 is involved in the initation of autophagosomes and PI3KC3-C2 is involved in the maturation of autophagosomes and endocytosis. Beclin 1 also plays a role in antiviral host defense.