Enables identical protein binding activity. Involved in cellular response to UV and release of cytochrome c from mitochondria. Acts upstream of or within several processes, including apoptotic signaling pathway; cellular calcium ion homeostasis; and lymphocyte apoptotic process. Located in cytosol; endoplasmic reticulum; and mitochondrial membrane. Is integral component of mitochondrial outer membrane. Part of BAK complex. Is expressed in several structures, including alimentary system; brain; branchial arch; genitourinary system; and hemolymphoid system gland. Human ortholog(s) of this gene implicated in ataxia telangiectasia and cervix carcinoma. Orthologous to human BAK1 (BCL2 antagonist/killer 1). [provided by Alliance of Genome Resources, Apr 2022]