May be required for normal outer mitochondrial membrane dynamics . Required for coatomer-mediated retrograde transport in certain cells (By similarity). May recruit other proteins to membranes with high curvature. May promote membrane fusion . Involved in activation of caspase-dependent apoptosis by promoting BAX/BAK1 activation . Isoform 1 acts proapoptotic in fibroblasts (By similarity). Involved in caspase-independent apoptosis during nutrition starvation and involved in the regulation of autophagy. Activates lipid kinase activity of PIK3C3 during autophagy probably by associating with the PI3K complex II (PI3KC3-C2) . Associated with PI3KC3-C2 during autophagy may regulate the trafficking of ATG9A from the Golgi complex to the peripheral cytoplasm for the formation of autophagosomes by inducing Golgi membrane tubulation and fragmentation . Involved in regulation of degradative endocytic trafficking and cytokinesis, probably in the context of PI3KC3-C2 . Isoform 2 acts antiapoptotic in neuronal cells; involved in maintenance of mitochondrial morphology and promotes neuronal viability (By similarity).
Subcellular locations: Cytoplasm, Golgi apparatus membrane, Mitochondrion outer membrane, Cytoplasmic vesicle, Autophagosome membrane, Midbody
Association with the Golgi apparatus depends on the cell type (By similarity). Following starvation colocalizes with ATG5 and LC3 autophagy-related protein(s)on autophagosomal membranes .
Highly expressed in heart, skeletal muscle, kidney and placenta. Detected at lower levels in brain, colon, thymus, spleen, liver, small intestine, lung and peripheral blood leukocytes.