Tankyrase-1 Ankyrin Repeats Form an Adaptable Binding Platform for Targets of ADP-Ribose Modification.
The poly(ADP-ribose) polymerase enzyme Tankyrase-1 (TNKS) regulates multiple cellular processes and interacts with diverse proteins using five ankyrin repeat clusters (ARCs). There are limited structural insights into functional roles of the multiple ARCs of TNKS. Here we present the ARC1-3 crystal structure and employ small-angle X-ray scattering (SAXS) to investigate solution conformations of the complete ankyrin repeat domain. Mutagenesis and binding studies using the bivalent TNKS binding domain of Axin1 demonstrate that only certain ARC combinations function together. The physical basis for these restrictions is explained by both rigid and flexible ankyrin repeat elements determined in our structural analysis. SAXS analysis is consistent with a dynamic ensemble of TNKS ankyrin repeat conformations modulated by Axin1 interaction. TNKS ankyrin repeat domain is thus an adaptable binding platform with structural features that can explain selectivity toward diverse proteins, and has implications for TNKS positioning of bound targets for poly(ADP-ribose) modification.
Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Travis
T
Eisemann
Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Michael
M
McCauley
Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3T1J4, Canada.
Marie-France
MF
Langelier
Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Kushol
K
Gupta
Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
Swati
S
Roy
Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Gregory D
GD
Van Duyne
Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA; Department of Biochemistry and Molecular Medicine, Université de Montréal, Montréal, QC H3T1J4, Canada. Electronic address: john.pascal@umontreal.ca.
John M
JM
Pascal
D000246:Adenosine Diphosphate Ribose; D017089:Ankyrin Repeat; D060466:Axin Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D016296:Mutagenesis; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D053838:Scattering, Small Angle; D013379:Substrate Specificity; D038501:Tankyrases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D000246:Adenosine Diphosphate Ribose; D060466:Axin Protein; D038501:Tankyrases; C555451:AXIN1 protein, human; C418109:TNKS protein, human