Predicted to enable Atg12 transferase activity; Atg8-family conjugating enzyme activity; and Atg8-family ligase activity. Predicted to be involved in autophagy of mitochondrion; macroautophagy; and mitochondrial fragmentation involved in apoptotic process. Predicted to act upstream of or within autophagy and protein transport. Predicted to be located in cytoplasm. Predicted to be active in cytosol and phagophore assembly site. Is expressed in several structures, including heart; liver; male organism; muscle; and yolk syncytial layer. Orthologous to human ATG3 (autophagy related 3).