Bcl-2/E1B 19 kDa-interacting protein 3-like protein (Bnip3L) interacts with bcl-2/Bcl-xL and induces apoptosis by altering mitochondrial membrane permeability.
We have previously reported on cloning of the human gene encoding Bcl-2/adenovirus E1B 19 kDa-interacting protein 3-like protein (Bnip3L) and its growth inhibitory effect on cancer cells. Here we show that Bnip3L contains a motif similar to the BH3 domain which is conserved in Bcl-2 family proteins as well as containing a membrane-anchoring domain, and that Bnip3L interacts with Bcl-2 and Bcl-xL. Immunofluorescence microscopy revealed that Bnip3L was localized in the mitochondria, when in the presence of the membrane-anchoring domain. Transient expression of Bnip3L induced apoptosis of Rat-1 and HeLa cells and mutational analysis revealed that the BH3 domain and the membrane-anchoring domain were required for Bnip3L to induce cell death. Addition of recombinant Bnip3L to isolated mitochondria induced membrane potential loss and cytochrome c release both of which have been suggested to be prerequisite for apoptotic cell death. These results suggest that Bnip3L is one of the BH3-containing pro-apoptotic proteins and that it targets the mitochondria when inducing apoptosis.
Imazu
T
T
Department of Medical Genetics, Biomedical Research Center, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Shimizu
S
S
Tagami
S
S
Matsushima
M
M
Nakamura
Y
Y
Miki
T
T
Okuyama
A
A
Tsujimoto
Y
Y
D017501:Adenovirus E1B Proteins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D019556:COS Cells; D002417:Cattle; D002460:Cell Line; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D011817:Rabbits; D051381:Rats; D017386:Sequence Homology, Amino Acid; D025521:Tumor Suppressor Proteins; D051020:bcl-X Protein
D017501:Adenovirus E1B Proteins; C494811:BCL2L1 protein, human; C090121:BNIP3 protein, human; C116838:BNIP3L protein, human; C494813:Bcl2l1 protein, rat; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D025521:Tumor Suppressor Proteins; D051020:bcl-X Protein