Beclin 1

Domain

The coiled coil domain can form antiparallel homodimers and mediates dimerization with the coiled coil domains of ATG14 or UVRAG involved in the formation of PI3K complexes.

The C-terminal evolutionary conserved domain (ECD) contains poly-Gln-binding domains such as the ATXN3 poly-Gln motif, consistent with structural docking models revealing two highly scored poly-Gln-binding pockets in the ECD (PubMed:28445460). As some binding is observed with BECN1 lacking the ECD, other domains of BECN1 may also interact with ATXN3 (PubMed:28445460).

Function

Plays a central role in autophagy (PubMed:23184933, PubMed:28445460). Acts as core 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. Involved in regulation of degradative endocytic trafficking and required for the abcission step in cytokinesis, probably in the context of PI3KC3-C2 (PubMed:20643123, PubMed:20208530, PubMed:26783301). Essential for the formation of PI3KC3-C2 but not PI3KC3-C1 PI3K complex forms. Involved in endocytosis (PubMed:25275521). Protects against infection by a neurovirulent strain of Sindbis virus (PubMed:9765397). May play a role in antiviral host defense.

Beclin-1-C 35 kDa localized to mitochondria can promote apoptosis; it induces the mitochondrial translocation of BAX and the release of proapoptotic factors.

Post-translational modifications

Phosphorylation at Thr-119 by DAPK1 reduces its interaction with BCL2 and BCL2L1 and promotes induction of autophagy (PubMed:19180116). In response to autophagic stimuli, phosphorylated at serine residues by AMPK in an ATG14-dependent manner, and this phosphorylation is critical for maximally efficient autophagy (PubMed:23878393).

Polyubiquitinated by NEDD4, both with 'Lys-11'- and 'Lys-63'-linkages (PubMed:21936852). 'Lys-11'-linked polyubiquitination leads to degradation and is enhanced when the stabilizing interaction partner VPS34 is depleted (PubMed:21936852). Deubiquitinated by USP10 and USP13, leading to stabilize the PIK3C3/VPS34-containing complexes (PubMed:21962518). Polyubiquitinated at Lys-402 with 'Lys-48'-linkages (PubMed:28445460). 'Lys-48'-linked polyubiquitination of Lys-402 leads to degradation (PubMed:28445460). Deubiquitinated by ATXN3, leading to stabilization (PubMed:28445460).

Proteolytically processed by caspases including CASP8 and CASP3; the C-terminal fragments lack autophagy-inducing capacity and are proposed to induce apoptosis. Thus the cleavage is proposed to be an determinant to switch from autophagy to apoptosis pathways affecting cellular homeostasis including viral infections and survival of tumor cells.

Sequence similarities

Belongs to the beclin family.

Tissue specificity

Ubiquitous.

Cellular localization

• Cytoplasm
• Golgi apparatus
• Trans-Golgi network membrane
• Peripheral membrane protein
• Endosome membrane
• Peripheral membrane protein
• Endoplasmic reticulum membrane
• Peripheral membrane protein
• Mitochondrion membrane
• Peripheral membrane protein
• Endosome
• Cytoplasmic vesicle
• Autophagosome
• Interaction with ATG14 promotes translocation to autophagosomes. Expressed in dendrites and cell bodies of cerebellar Purkinje cells (By similarity).
• Beclin-1-C 35 kDa
• Mitochondrion
• Nucleus
• Cytoplasm
• Beclin-1-C 37 kDa
• Mitochondrion

Alternative names

• Beclin-1
• Coiled-coil myosin-like BCL2-interacting protein
• Protein GT197
• BECN1
• GT197

Database links

• entrezGene:8678
• omim:604378
• swissprot:Q14457

Target type

Proteins

Primary research area

Oncology

Other research areas

• Neuroscience

Molecular weight

51896Da