Bcl-2 mutants with restricted subcellular location reveal spatially distinct pathways for apoptosis in different cell types.
Human Bcl-2 is located in multiple intracellular membranes when expressed in MDCK and Rat-1/myc cells. We restricted expression to the endoplasmic reticulum or mitochondria by exchanging the Bcl-2 carboxy-terminal insertion sequence for an equivalent sequence from cytochrome b5 or ActA, respectively. MDCK cells are protected from serum deprivation-induced apoptosis by both wild-type Bcl-2 and the mutant targeted to mitochondria but not by the mutant targeted to endoplasmic reticulum. In contrast, when expressed in Rat-1/myc cells, the Bcl-2 mutant located at the endoplasmic reticulum is more effective than that targeted to mitochondria. In MDCK cells both mutants bind Bax as effectively as wild-type, demonstrating that Bax binding is not sufficient to prevent apoptosis.
Zhu
W
W
Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada.
Cowie
A
A
Wasfy
G W
GW
Penn
L Z
LZ
Leber
B
B
Andrews
D W
DW
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002460:Cell Line; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D007668:Kidney / Q000166:cytology; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; C494827:Bax protein, mouse; C494828:Bax protein, rat; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016271:Proto-Oncogene Proteins c-myc; D011993:Recombinant Fusion Proteins; D051028:bcl-2-Associated X Protein