Catalytic subunit of the PI3K complex that mediates formation of phosphatidylinositol 3-phosphate; different complex forms are believed to play a role in multiple membrane trafficking pathways: PI3KC3-C1 is involved in initiation of autophagosomes and PI3KC3-C2 in maturation of autophagosomes and endocytosis ( ). As part of PI3KC3-C1, promotes endoplasmic reticulum membrane curvature formation prior to vesicle budding . Involved in regulation of degradative endocytic trafficking and required for the abcission step in cytokinesis, probably in the context of PI3KC3-C2 (, ). Involved in the transport of lysosomal enzyme precursors to lysosomes (By similarity). Required for transport from early to late endosomes (By similarity).
(Microbial infection) Kinase activity is required for SARS coronavirus-2/SARS-CoV-2 replication.
Subcellular locations: Midbody, Late endosome, Cytoplasmic vesicle, Autophagosome
As component of the PI3K complex I localized to pre-autophagosome structures. As component of the PI3K complex II localized predominantly to endosomes . Localizes also to discrete punctae along the ciliary axoneme and to the base of the ciliary axoneme (By similarity).
Ubiquitously expressed, with a highest expression in skeletal muscle.