TY - JOUR
T1 - Structural basis of control of inward rectifier Kir2 channel gating by bulk anionic phospholipids
AU - Lee, Sun Joo
AU - Ren, Feifei
AU - Zangerl-Plessl, Eva Maria
AU - Heyman, Sarah
AU - Stary-Weinzinger, Anna
AU - Yuan, Peng
AU - Nichols, Colin G.
N1 - Funding Information:
ACKNOWLEDGMENTS The authors are very grateful to Dr. Roderick MacKinnon for providing the chicken Kir2.2 DNA construct that we used for P. pastoris expression and crystallization. We thank the staffs at APS beamlines 24-ID-C/E, especially Dr. Kay Perry for assistance with data collection and Dr. Zengqin Deng for help with crystallization. This work was supported by National Institutes of Health grant HL54171 (to C.G. Nichols), American Heart Association fellowship 15POST22390016 (to S.-J. Lee), Center for the Investigation and Membrane Excitability Diseases Pilot and Feasibility grant CIM ED-15-01 (to P. Yuan), and Austrian Science Fund grants W1232 (to E.-M. Zangerl-Plessl and A. Stary-Weinzinger) and I-2101-B26 (to A. Stary-Weinzinger). The computational simulations were carried out using the Vienna Scientific Cluster (VSC). The authors declare no competing financial interests. Author contributions: S.-J. Lee and C.G. Nichols conceived of the project. S.-J. Lee, S. Heyman, and F. Ren carried out experiments. P. Yuan supervised the crystallography and analyses. The molecular modeling was carried out by E.-M. Zangerl-Plessl and A. Stary-Weinzinger. C.G. Nichols, S.-J. Lee, and F. Ren analyzed the data. C.G. Nichols and S.-J. Lee wrote the paper, which was edited by F. Ren, P. Yuan, and A. Stary-Weinzinger.
Publisher Copyright:
© 2016 Lee et al.
PY - 2016
Y1 - 2016
N2 - Inward rectifier potassium (Kir) channel activity is controlled by plasma membrane lipids. Phosphatidylinositol- 4,5-bisphosphate (PIP2) binding to a primary site is required for opening of classic inward rectifier Kir2.1 and Kir2.2 channels, but interaction of bulk anionic phospholipid (PL-) with a distinct second site is required for high PIP2sensitivity. Here we show that introduction of a lipid-partitioning tryptophan at the second site (K62W) generates high PIP2sensitivity, even in the absence of PL-. Furthermore, high-resolution x-ray crystal structures of Kir2.2[K62W], with or without added PIP2 (2.8- and 2.0-Å resolution, respectively), reveal tight tethering of the C-terminal domain (CTD) to the transmembrane domain (TMD) in each condition. Our results suggest a refined model for phospholipid gating in which PL- binding at the second site pulls the CTD toward the membrane, inducing the formation of the high-affinity primary PIP2site and explaining the positive allostery between PL- binding and PIP2sensitivity.
AB - Inward rectifier potassium (Kir) channel activity is controlled by plasma membrane lipids. Phosphatidylinositol- 4,5-bisphosphate (PIP2) binding to a primary site is required for opening of classic inward rectifier Kir2.1 and Kir2.2 channels, but interaction of bulk anionic phospholipid (PL-) with a distinct second site is required for high PIP2sensitivity. Here we show that introduction of a lipid-partitioning tryptophan at the second site (K62W) generates high PIP2sensitivity, even in the absence of PL-. Furthermore, high-resolution x-ray crystal structures of Kir2.2[K62W], with or without added PIP2 (2.8- and 2.0-Å resolution, respectively), reveal tight tethering of the C-terminal domain (CTD) to the transmembrane domain (TMD) in each condition. Our results suggest a refined model for phospholipid gating in which PL- binding at the second site pulls the CTD toward the membrane, inducing the formation of the high-affinity primary PIP2site and explaining the positive allostery between PL- binding and PIP2sensitivity.
UR - http://www.scopus.com/inward/record.url?scp=84990841687&partnerID=8YFLogxK
U2 - 10.1085/jgp.201611616
DO - 10.1085/jgp.201611616
M3 - Article
C2 - 27527100
AN - SCOPUS:84990841687
SN - 0022-1295
VL - 148
SP - 227
EP - 237
JO - Journal of General Physiology
JF - Journal of General Physiology
IS - 3
ER -