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Lee EF, Grabow S, Chappaz S, Dewson G, Hockings C, Kluck RM, Debrincat MA, Gray DH, Witkowski MT, Evangelista M, Pettikiriarachchi A, Bouillet P, Lane RM, Czabotar PE, Colman PM, Smith BJ, Kile BT, Fairlie WD. Physiological restraint of Bak by Bcl-xL is essential for cell survival. Genes Dev 2016; 30:1240-50. [PMID: 27198225 PMCID: PMC4888843 DOI: 10.1101/gad.279414.116] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/18/2016] [Indexed: 12/21/2022]
Abstract
Lee et al. describe a mutation in mouse and human Bak that specifically disrupts its interaction with the prosurvival protein Bcl-xL. In vivo, loss of Bcl-xL binding to Bak led to significant defects in T-cell and blood platelet survival. Due to the myriad interactions between prosurvival and proapoptotic members of the Bcl-2 family of proteins, establishing the mechanisms that regulate the intrinsic apoptotic pathway has proven challenging. Mechanistic insights have primarily been gleaned from in vitro studies because genetic approaches in mammals that produce unambiguous data are difficult to design. Here we describe a mutation in mouse and human Bak that specifically disrupts its interaction with the prosurvival protein Bcl-xL. Substitution of Glu75 in mBak (hBAK Q77) for leucine does not affect the three-dimensional structure of Bak or killing activity but reduces its affinity for Bcl-xL via loss of a single hydrogen bond. Using this mutant, we investigated the requirement for physical restraint of Bak by Bcl-xL in apoptotic regulation. In vitro, BakQ75L cells were significantly more sensitive to various apoptotic stimuli. In vivo, loss of Bcl-xL binding to Bak led to significant defects in T-cell and blood platelet survival. Thus, we provide the first definitive in vivo evidence that prosurvival proteins maintain cellular viability by interacting with and inhibiting Bak.
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Affiliation(s)
- Erinna F Lee
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia; Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia; Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria 3084, Australia; School of Cancer Medicine, La Trobe University, Melbourne, Victoria 3084, Australia
| | - Stephanie Grabow
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Stephane Chappaz
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Grant Dewson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Colin Hockings
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ruth M Kluck
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Marlyse A Debrincat
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Daniel H Gray
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Matthew T Witkowski
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Marco Evangelista
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria 3084, Australia; School of Cancer Medicine, La Trobe University, Melbourne, Victoria 3084, Australia
| | - Anne Pettikiriarachchi
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Philippe Bouillet
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Rachael M Lane
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Peter M Colman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Brian J Smith
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Benjamin T Kile
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - W Douglas Fairlie
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia; Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia; Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria 3084, Australia; School of Cancer Medicine, La Trobe University, Melbourne, Victoria 3084, Australia
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Lee EF, Fedorova A, Zobel K, Boyle MJ, Yang H, Perugini MA, Colman PM, Huang DCS, Deshayes K, Fairlie WD. Novel Bcl-2 homology-3 domain-like sequences identified from screening randomized peptide libraries for inhibitors of the pro-survival Bcl-2 proteins. J Biol Chem 2009; 284:31315-26. [PMID: 19748896 DOI: 10.1074/jbc.m109.048009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interactions between Bcl-2 homology-3 (BH3)-only proteins and their pro-survival Bcl-2 family binding partners initiate the intrinsic apoptosis pathway. These interactions are mediated by a short helical motif, the BH3 domain, on the BH3-only protein, which inserts into a hydrophobic groove on the pro-survival molecule. To identify novel peptidic ligands that bind Mcl-1, a pro-survival protein relative of Bcl-2, both human and mouse Mcl-1 were screened against large randomized phage-displayed peptide libraries. We identified a number of 16-mer peptides with sub-micromolar affinity that were highly selective for Mcl-1, as well as being somewhat selective for the species of Mcl-1 (human or mouse) against which the library was panned. Interestingly, these sequences all strongly resembled natural BH3 domain sequences. By switching residues within the best of the human Mcl-1-binding sequences, or extending beyond the core sequence identified, we were able to alter the pro-survival protein interaction profile of this peptide such that it now bound all members tightly and was a potent killer when introduced into cells. Introduction of an amide lock constraint within this sequence also increased its helicity and binding to pro-survival proteins. These data provide new insights into the determinants of BH3 domain:pro-survival protein affinity and selectivity.
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Affiliation(s)
- Erinna F Lee
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Pde., Parkville, Victoria 3052, Australia
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Lee EF, Czabotar PE, van Delft MF, Michalak EM, Boyle MJ, Willis SN, Puthalakath H, Bouillet P, Colman PM, Huang DCS, Fairlie WD. A novel BH3 ligand that selectively targets Mcl-1 reveals that apoptosis can proceed without Mcl-1 degradation. ACTA ACUST UNITED AC 2008; 180:341-55. [PMID: 18209102 PMCID: PMC2213596 DOI: 10.1083/jcb.200708096] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Like Bcl-2, Mcl-1 is an important survival factor for many cancers, its expression contributing to chemoresistance and disease relapse. However, unlike other prosurvival Bcl-2–like proteins, Mcl-1 stability is acutely regulated. For example, the Bcl-2 homology 3 (BH3)–only protein Noxa, which preferentially binds to Mcl-1, also targets it for proteasomal degradation. In this paper, we describe the discovery and characterization of a novel BH3-like ligand derived from Bim, BimS2A, which is highly selective for Mcl-1. Unlike Noxa, BimS2A is unable to trigger Mcl-1 degradation, yet, like Noxa, BimS2A promotes cell killing only when Bcl-xL is absent or neutralized. Furthermore, killing by endogenous Bim is not associated with Mcl-1 degradation. Thus, functional inactivation of Mcl-1 does not always require its elimination. Rather, it can be efficiently antagonized by a BH3-like ligand tightly engaging its binding groove, which is confirmed here with a structural study. Our data have important implications for the discovery of compounds that might kill cells whose survival depends on Mcl-1.
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Affiliation(s)
- Erinna F Lee
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3050, Australia
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SUN L, CHU T, WANG Y, WANG X. Radiolabeling and biodistribution of a nasopharyngeal carcinoma-targeting peptide identified by in vivo phage display. Acta Biochim Biophys Sin (Shanghai) 2007; 39:624-32. [PMID: 17687498 DOI: 10.1111/j.1745-7270.2007.00321.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
A dodecapeptide EDIKPKTSLAFR ligand targeting CEN-1 human nasopharyngeal carcinoma (NPC) was identified by in vivo phage display. Two tridecapeptides and their derivatives, named YR13 (YEDIKPKTSLAFR), EY13 (EDIKPKTSLAFRY), EY13-NH2 (EDIKPKTSLAFRY-NH2) and Fmoc-YR13 (Fmoc-YEDIKPKTSLAFR), were synthesized and radiolabeled with 131I. The stability in vitro, biodistribution and tissue distribution of selected phage particles in mice bearing NPC tumor were determined, and plasma metabolites analysis of radiolabeled peptides was carried out. Although Fmoc and NH2 groups could protect the peptide from deiodination, only Fmoc group inhibited the binding of Fmoc-YR13 to NPC tumors. The compound EY13-NH2, the C-terminal amide of peptide EY13, had the greatest serum stability, the least deiodination, and showed favorable tumor/blood ratios. The selected phage particles (phage 3 or phage 5) were more concentrated in NPC tumors than the control phage (initial phage display peptide library). EY13 could also inhibit the binding of selected phage particles to tumors. The results indicated that EDIKPKTSLAFR was a good candidate in diagnostic and therapeutic NPC.
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Affiliation(s)
- Liyan SUN
- Bejing National Laboratory for Molecular Sciences, Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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Ryan DP, Sunde M, Kwan AHY, Marianayagam NJ, Nancarrow AL, Vanden Hoven RN, Thompson LS, Baca M, Mackay JP, Visvader JE, Matthews JM. Identification of the Key LMO2-binding Determinants on Ldb1. J Mol Biol 2006; 359:66-75. [PMID: 16616188 DOI: 10.1016/j.jmb.2006.02.074] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 02/27/2006] [Accepted: 02/28/2006] [Indexed: 11/16/2022]
Abstract
The overexpression of LIM-only protein 2 (LMO2) in T-cells, as a result of chromosomal translocations, retroviral insertion during gene therapy, or in transgenic mice models, leads to the onset of T-cell leukemias. LMO2 comprises two protein-binding LIM domains that allow LMO2 to interact with multiple protein partners, including LIM domain-binding protein 1 (Ldb1, also known as CLIM2 and NLI), an essential cofactor for LMO proteins. Sequestration of Ldb1 by LMO2 in T-cells may prevent it binding other key partners, such as LMO4. Here, we show using protein engineering and enzyme-linked immunosorbent assay (ELISA) methodologies that LMO2 binds Ldb1 with a twofold lower affinity than does LMO4. Thus, excess LMO2 rather than an intrinsically higher binding affinity would lead to sequestration of Ldb1. Both LIM domains of LMO2 are required for high-affinity binding to Ldb1 (K(D) = 2.0 x 10(-8) M). However, the first LIM domain of LMO2 is primarily responsible for binding to Ldb1 (K(D) = 2.3 x 10(-7) M), whereas the second LIM domain increases binding by an order of magnitude. We used mutagenesis in combination with yeast two-hybrid analysis, and phage display selection to identify LMO2-binding "hot spots" within Ldb1 that locate to the LIM1-binding region. The delineation of this region reveals some specific differences when compared to the equivalent LMO4:Ldb1 interaction that hold promise for the development of reagents to specifically bind LMO2 in the treatment of leukemia.
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Affiliation(s)
- Daniel P Ryan
- School of Molecular and Microbial Biosciences, University of Sydney, NSW, Australia
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Fairlie WD, Uboldi AD, McCoubrie JE, Wang CC, Lee EF, Yao S, De Souza DP, Mifsud S, Metcalf D, Nicola NA, Norton RS, Baca M. Affinity maturation of leukemia inhibitory factor and conversion to potent antagonists of signaling. J Biol Chem 2003; 279:2125-34. [PMID: 14585833 DOI: 10.1074/jbc.m310103200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leukemia inhibitory factor (LIF)-induced cell signaling occurs following sequential binding to the LIF receptor alpha-chain (LIFR), then to the gp130 co-receptor used by all members of the interleukin-6 family of cytokines. By monovalently displaying human LIF on the surface of M13 phage and randomizing clusters of residues in regions predicted to be important for human LIFR binding, we have identified mutations, which lead to significant increases in affinity for binding to LIFR. Six libraries were constructed in which regions of 4-6 amino acids were randomized then panned against LIFR. Mutations identified in three distinct clusters, residues 53-57, 102-103, and 150-155, gave rise to proteins with significantly increased affinity for binding to both human and mouse LIFR. Combining the mutations for each of these regions further increased the affinity, such that the best mutants bound to human LIFR with >1000-fold higher affinity than wild-type human LIF. NMR analysis indicated that the mutations did not alter the overall structure of the molecule relative to the native protein, although some local changes occurred in the vicinity of the substituted residues. Despite increases in LIFR binding affinity, these mutants did not show any increase in activity as agonists of LIF-induced proliferation of Ba/F3 cells expressing human LIFR and gp130 compared with wild-type LIF. Incorporation of two additional mutations (Q29A and G124R), which were found to abrogate cell signaling, led to the generation of highly potent antagonists of both human and murine LIF-induced bioactivity.
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Affiliation(s)
- W Douglas Fairlie
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia
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