BECN1

Intracellular

Low cell type specificity

Low immune cell specificity

Low cell line specificity

A homodimeric form is proposed to exist; this metastable form readily transits to ATG14- or UVRAG-containing complexes with BECN1:UVRAG being more stable than BECN1:ATG14 (By similarity). Component of the PI3K (PI3KC3/PI3K-III/class III phosphatidylinositol 3-kinase) complex the core of which is composed of the catalytic subunit PIK3C3, the regulatory subunit PIK3R4 and BECN1 associating with additional regulatory/auxilliary subunits to form alternative complex forms. Alternative complex forms containing a forth regulatory subunit in a mutually exclusive manner are PI3K complex I (PI3KC3-C1) containing ATG14, and PI3K complex II (PI3KC3-C2) containing UVRAG. PI3KC3-C1 displays a V-shaped architecture with PIK3R4 serving as a bridge between PIK3C3 and the ATG14:BECN1 subcomplex (PubMed:18843052, PubMed:19050071, PubMed:19270696, PubMed:23878393, PubMed:25490155). Both, PI3KC3-C1 and PI3KC3-C2, can associate with further regulatory subunits, such as RUBCN, SH3GLB1/Bif-1 and AMBRA1 (PubMed:20643123, PubMed:19270696). PI3KC3-C1 probably associates with PIK3CB (By similarity). Interacts with AMBRA1, GOPC, GRID2 (PubMed:21358617). Forms a complex with PPP2CA and AMBRA1; AMBRA1 and BECN1 components of the complex regulate MYC stability via different pathways (PubMed:25803737). Interacts with BCL2 and BCL2L1 isoform Bcl-X(L); the interaction inhibits BECN1 function in promoting autophagy by interfering with the formation of the PI3K complex (PubMed:9765397, PubMed:16179260, PubMed:17446862, PubMed:18570871, PubMed:21358617, PubMed:22498477, PubMed:17337444, PubMed:17659302). Interacts with cytosolic HMGB1; inhibits the interaction of BECN1 and BCL2 leading to promotion of autophagy (PubMed:20819940). Interacts with USP10, USP13, VMP1, DAPK1, RAB39A (PubMed:19180116, PubMed:17724469, PubMed:17337444, PubMed:21962518, PubMed:24349490). Interacts with the poly-Gln domain of ATXN3; the interaction causes deubiquitination at Lys-402 and stabilizes BECN1 (PubMed:28445460). Interacts with SLAMF1 (PubMed:22493499). Interacts with TRIM5; the interaction causes activation of BECN1 by causing its dissociation from its inhibitors BCL2 and TAB2 (PubMed:25127057). Interacts with active ULK1 (phosphorylated on 'Ser-317') and MEFV simultaneously (PubMed:26347139). Interacts with WDR81 and WDR91; negatively regulates the PI3 kinase/PI3K activity associated with endosomal membranes (PubMed:26783301). Interacts with LAPTM4B; competes with EGFR for LAPTM4B binding; regulates EGFR activity (PubMed:28479384). Interacts with TRIM50 (PubMed:29604308). Interacts with TRIM16. Interacts with ATG14; this interaction is increased in the absence of TMEM39A (PubMed:31806350). Interacts with WASHC1; preventing interaction with AMBRA1 and the DCX(AMBRA1) complex and subsequent ubiquitination (PubMed:23974797). Interacts with TRIM17 (PubMed:27562068). Interacts with BCL2L10/BCL-B (via BH1 domain) (PubMed:22498477). (Microbial infection) Interacts with human cytomegalovirus/HHV-5 protein TRS1. (Microbial infection) Interacts with murine gammaherpesvirus 68 M11. (Microbial infection) Interacts with herpes simplex virus 1 (HHV-1) protein ICP34.5; this interaction antagonizes the host autophagy response.