TY - JOUR
T1 - PUMA binding induces partial unfolding within BCL-xL to disrupt p53 binding and promote apoptosis
AU - Follis, Ariele Viacava
AU - Chipuk, Jerry E.
AU - Fisher, John C.
AU - Yun, Mi Kyung
AU - Grace, Christy R.
AU - Nourse, Amanda
AU - Baran, Katherine
AU - Ou, Li
AU - Min, Lie
AU - White, Stephen W.
AU - Green, Douglas R.
AU - Kriwacki, Richard W.
N1 - Funding Information:
We thank J.T. Opferman and S.W.G. Tait (St. Jude Children’s Research Hospital) for the Mx-Cre bak−/− baxf/− animals and MCF7 SMAC-GFP cells, respectively. The prokaryotic expression vectors for PUMAβ and BCL-xLΔLΔC were kindly provided by E. Eldering (Academic Medical Center, Amsterdam) and G. Wagner (Harvard University), respectively. We would like to acknowledge D. Miller (St. Jude Children’s Research Hospital) for help with synchrotron data collection. Southeast Regional Collaborative Access Team (SER-CAT) supporting institutions may be found at http://www.ser.aps.anl.gov. Use of the SER-CAT Advanced Photon Source was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. W-31-109-Eng-38. We would like to thank Bruker BioSpin and R. Weismann and W. Bermel for access to a 950-MHz NMR spectrometer. We also thank M. Madan Babu and A. Venkatakrishnan (Medical Research Council Laboratory of Molecular Biology, Cambridge, UK) for stimulating discussions and comments on the manuscript. This work was supported by NIH R01CA082491 and 1R01GM083159 (to R.W.K.), NIH R01GM52735 and R01GM96208 (to D.R.G.), NIH R01 CA157740 (to J.E.C.), the JJR Foundation (to J.E.C.), the William A. Spivak Fund (to J.E.C.), the Fridolin Charitable Trust (to J.E.C.), a National Cancer Institute Cancer Center Support Grant P30CA21765 (at St. Jude Children’s Research Hospital), research grant no. 5-FY11-74 from the March of Dimes Foundation (to J.E.C.) and the American Lebanese Syrian Associated Charities. J.C.F. is a recipient of the Alma and Hal Reagan Cancer Research fellowship provided by the University of Tennessee Health Sciences Center.
PY - 2013/3
Y1 - 2013/3
N2 - Following DNA damage, nuclear p53 induces the expression of PUMA, a BH3-only protein that binds and inhibits the antiapoptotic BCL-2 repertoire, including BCL-xL. PUMA, unique among BH3-only proteins, disrupts the interaction between cytosolic p53 and BCL-xL, allowing p53 to promote apoptosis via direct activation of the BCL-2 effector molecules BAX and BAK. Structural investigations using NMR spectroscopy and X-ray crystallography revealed that PUMA binding induced partial unfolding of two α-helices within BCL-xL. Wild-type PUMA or a PUMA mutant incapable of causing binding-induced unfolding of BCL-xL equivalently inhibited the antiapoptotic BCL-2 repertoire to sensitize for death receptor-activated apoptosis, but only wild-type PUMA promoted p53-dependent, DNA damage-induced apoptosis. Our data suggest that PUMA-induced partial unfolding of BCL-xL disrupts interactions between cytosolic p53 and BCL-xL, releasing the bound p53 to initiate apoptosis. We propose that regulated unfolding of BCL-xL provides a mechanism to promote PUMA-dependent signaling within the apoptotic pathways.
AB - Following DNA damage, nuclear p53 induces the expression of PUMA, a BH3-only protein that binds and inhibits the antiapoptotic BCL-2 repertoire, including BCL-xL. PUMA, unique among BH3-only proteins, disrupts the interaction between cytosolic p53 and BCL-xL, allowing p53 to promote apoptosis via direct activation of the BCL-2 effector molecules BAX and BAK. Structural investigations using NMR spectroscopy and X-ray crystallography revealed that PUMA binding induced partial unfolding of two α-helices within BCL-xL. Wild-type PUMA or a PUMA mutant incapable of causing binding-induced unfolding of BCL-xL equivalently inhibited the antiapoptotic BCL-2 repertoire to sensitize for death receptor-activated apoptosis, but only wild-type PUMA promoted p53-dependent, DNA damage-induced apoptosis. Our data suggest that PUMA-induced partial unfolding of BCL-xL disrupts interactions between cytosolic p53 and BCL-xL, releasing the bound p53 to initiate apoptosis. We propose that regulated unfolding of BCL-xL provides a mechanism to promote PUMA-dependent signaling within the apoptotic pathways.
UR - http://www.scopus.com/inward/record.url?scp=84874044758&partnerID=8YFLogxK
U2 - 10.1038/nchembio.1166
DO - 10.1038/nchembio.1166
M3 - Article
C2 - 23340338
AN - SCOPUS:84874044758
SN - 1552-4450
VL - 9
SP - 163
EP - 168
JO - Nature Chemical Biology
JF - Nature Chemical Biology
IS - 3
ER -