The PIK3R4 gene (PIK3R4 = acronym for phosphoinositide 3-kinase regulatory subunit 4) is located on chromosome 3q22.1 and encodes the protein phosphoinositide 3-kinase regulatory subunit 4, a regulatory subunit of the PI3K complex that mediates the formation of phosphatidylinositol-3-phosphate. Different forms of the complex are thought to play a role in several membrane trafficking pathways, such at the assembly of autophagosomes. Evidence suggests:
- PI3KC3-C1 is involved in the initiation of autophagosomes.
- PI3KC3-C2 in the maturation of autophagosomes and endocytosis.