Beclin-1 is a protein that in humans is encoded by the BECN1 gene. Beclin-1 is a mammalian ortholog of the yeast autophagy-related gene (Atg) 6 and BEC-1 in the C. elegans nematode. Beclin-1 participates in the regulation of autophagy and has an important role in development, tumorigenesis, and neurodegeneration. Beclin-1 and its binding partner class III phosphoinositide 3-kinase (PI3K), also named Vps34, are required for the initiation of the formation of the autophagosome in autophagy.