Scaffold protein component of the PI(3,5)P2 regulatory complex which regulates both the synthesis and turnover of phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2). Pentamerizes into a star-shaped structure and nucleates the assembly of the complex. The pentamer binds a single copy each of PIKFYVE and FIG4 and coordinates both PIKfyve kinase activity and FIG4 phosphatase activity, being required to maintain normal levels of phosphatidylinositol 3-phosphate (PtdIns(3)P) and phosphatidylinositol 5-phosphate (PtdIns(5)P) (PubMed:33098764). Plays a role in the biogenesis of endosome carrier vesicles (ECV) / multivesicular bodies (MVB) transport intermediates from early endosomes. Forms pentamers (PubMed:33098764, PubMed:18950639). Component of the PI(3,5)P2 regulatory complex/PAS complex, at least composed of PIKFYVE, FIG4 and VAC14. VAC14 nucleates the assembly of the complex and serves as a scaffold by pentamerizing into a star-shaped structure, which can bind a single copy each of PIKFYVE and FIG4 and coordinates their activities (PubMed:17556371, PubMed:18950639, PubMed:33098764). Interacts with NOS1 (PubMed:17161399). (Microbial infection) Interacts with HTLV-1 Tax. Mainly associated with membranes of the late endocytic pathway. Ubiquitously expressed. The C-terminal domain (residues 523-782) mediates pentameric interactions and is necessary for the formation and maintenance of the PI(3,5)P2 regulatory complex. The disease is caused by variants affecting the gene represented in this entry. Belongs to the VAC14 family. Unknown C-terminal region. Truncated N-terminus.