Versatile protein that is involved in regulation of different cellular pathways implicated in membrane trafficking. Involved in regulation of the COPI-dependent retrograde transport from Golgi and the endoplasmic reticulum by associating with the NRZ complex; the function is dependent on its binding to phosphatidylinositol 3-phosphate (PtdIns(3)P) (PubMed:16799551, PubMed:18552835, PubMed:20643123, PubMed:24056303, PubMed:28306502). During autophagy acts as regulatory subunit of the alternative PI3K complex II (PI3KC3-C2) that mediates formation of phosphatidylinositol 3-phosphate and is believed to be involved in maturation of autophagosomes and endocytosis. Activates lipid kinase activity of PIK3C3 (PubMed:16799551, PubMed:20643123, PubMed:24056303, PubMed:28306502). Involved in the regulation of degradative endocytic trafficking and cytokinesis, and in regulation of ATG9A transport from the Golgi to the autophagosome; the functions seems to implicate its association with PI3KC3-C2 (PubMed:16799551, PubMed:20643123, PubMed:24056303). Involved in maturation of autophagosomes and degradative endocytic trafficking independently of BECN1 but depending on its association with a class C Vps complex (possibly the HOPS complex); the association is also proposed to promote autophagosome recruitment and activation of Rab7 and endosome-endosome fusion events (PubMed:18552835, PubMed:28306502). Enhances class C Vps complex (possibly HOPS complex) association with a SNARE complex and promotes fusogenic SNARE complex formation during late endocytic membrane fusion (PubMed:24550300). In case of negative-strand RNA virus infection is required for efficient virus entry, promotes endocytic transport of virions and is implicated in a VAMP8-specific fusogenic SNARE complex assembly (PubMed:24550300). Involved in maintaining chromosomal stability. Promotes DNA double-strand break (DSB) repair by association with DNA-dependent protein kinase complex DNA-PK and activating it in non-homologous end joining (NHEJ) (PubMed:22542840). Required for centrosome stability and proper chromosome segregation (PubMed:22542840). Component of the PI3K (PI3KC3/PI3K-III/class III phosphatidylinositol 3-kinase) complex II (PI3KC3-C2) in which the core composed of the catalytic subunit PIK3C3, the regulatory subunit PIK3R4 and BECN1 is associated with UVRAG; in the complex interacts directly with BECN1. PI3KC3-C2 can associate with further regulatory subunits such as RUBCN and probably SH3GLB1/Bif-1 (PubMed:16799551, PubMed:18843052, PubMed:19050071, PubMed:19270696, PubMed:20643123, PubMed:23878393, PubMed:24056303). Interacts with SH3GLB1; UVRAG bridges the interaction to BECN1 indicative for an association with the PI3K complex PI3KC3-C2 (PubMed:17891140). Interacts with RINT1. Associates with the NRZ complex under basal conditions and dissociates from it under autophagy conditions to associate with the PI3K complex; these complex associations seem to be mutually exclusive (PubMed:24056303). Interacts with VPS16; VPS11; VPS18; VPS33 (VPS33A or VPS33B) and VPS39; indicative for an association with a class C Vps tethering complex (possibly the HOPS complex) (PubMed:18552835, PubMed:25533187). Interacts with RAB7A; RAB7A competes with UVRAG for RUBCN binding (PubMed:25533187, PubMed:20974968). Interacts with STX7, VTI1B, STX8 (PubMed:24550300). Interacts with PRKDC, XRCC6 and XRCC5; indicative for an association with the DNA-dependent protein kinase complex DNA-PK. Interacts with CEP63 (PubMed:22542840). Directly interacts with FEZ1 and SCOC; the interaction with SCOC is reduced by amino acid starvation, but the complex is stabilized in the presence of FEZ1 (PubMed:22354037). Interacts with BECN1P1/BECN2 (PubMed:23954414). Interacts with SLAMF1 (PubMed:22493499). Interacts with RUBCNL/PACER; promoting targeting of UVRAG to autophagosome (PubMed:28306502). Colocalizes with RAB9-positive compartments involved in retrograde transport from late endosomes to trans-Golgi network. Colocalization with early endosomes is only partial (PubMed:24056303). Recruited to autophagosome following interaction with RUBCNL/PACER (PubMed:28306502). Highly expressed in brain, lung, kidney and liver. Phosphorylated at Ser-498 by MTOR under basal conditions; increases the interaction with RUBCN implicated in inhibitory effect of RUBCN on PI3KC3 and decreases interaction with RAB7,A and VPS16 and VPS39 (indicative for a class C Vps complex, possibly the HOPS complex) (PubMed:25533187). A chromosomal aberration involving UVRAG has been observed in a patient with heterotaxy (left-right axis malformation). Inversion Inv(11)(q13.5;q25).