Receptor-selective mutants of apoptosis-inducing ligand 2/tumor necrosis factor-related apoptosis-inducing ligand reveal a greater contribution of death receptor (DR) 5 than DR4 to apoptosis signaling.
Apoptosis-inducing ligand 2 (Apo2L), also called tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), triggers programmed cell death in various types of cancer cells but not in most normal cells. Apo2L/TRAIL is a homotrimeric protein that interacts with five receptors: death receptor 4 (DR4) and DR5 mediate apoptosis activation, whereas decoy receptor 1 (DcR1), DcR2, and osteoprotegerin counteract this function. Many cancer cell lines express both DR4 and DR5, and each of these receptors can initiate apoptosis independently of the other. However, the relative contribution of DR4 and DR5 to ligand-induced apoptosis is unknown. To investigate this question, we generated death receptor-selective Apo2L/TRAIL variants using a novel approach that enables phage display of mutated trimeric proteins. Selective binding to DR4 or DR5 was achieved with three to six-ligand amino acid substitutions. The DR4-selective Apo2L/TRAIL variants examined in this study showed a markedly reduced ability to trigger apoptosis, whereas the DR5-selective variants had minimally decreased or slightly increased apoptosis-inducing activity. These results suggest that DR5 may contribute more than DR4 to Apo2L/TRAIL-induced apoptosis in cancer cells that express both death receptors.
Kelley
Robert F
RF
Department of Protein Engineering, Genentech, Inc., South San Francisco, California 94080, USA. rk@gene.com
Totpal
Klara
K
Lindstrom
Stephanie H
SH
Mathieu
Mary
M
Billeci
Karen
K
Deforge
Laura
L
Pai
Roger
R
Hymowitz
Sarah G
SG
Ashkenazi
Avi
A
D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D006801:Humans; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000737:chemistry / Q000502:physiology*; D015398:Signal Transduction; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505639:TNFRSF10B protein, human; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha