Structural insights into GIRK2 channel modulation by cholesterol and PIP2

Yamuna Kalyani Mathiharan; Ian W. Glaaser; Yulin Zhao; Michael J. Robertson; Georgios Skiniotis; Paul A. Slesinger

doi:10.1016/j.celrep.2021.109619

Structural insights into GIRK2 channel modulation by cholesterol and PIP₂

Yamuna Kalyani Mathiharan, Ian W. Glaaser, Yulin Zhao, Michael J. Robertson, Georgios Skiniotis, Paul A. Slesinger

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Abstract

G-protein-gated inwardly rectifying potassium (GIRK) channels are important for determining neuronal excitability. In addition to G proteins, GIRK channels are potentiated by membrane cholesterol, which is elevated in the brains of people with neurodegenerative diseases such as Alzheimer's dementia and Parkinson's disease. The structural mechanism of cholesterol modulation of GIRK channels is not well understood. In this study, we present cryo- electron microscopy (cryoEM) structures of GIRK2 in the presence and absence of the cholesterol analog cholesteryl hemisuccinate (CHS) and phosphatidylinositol 4,5-bisphosphate (PIP₂). The structures reveal that CHS binds near PIP₂ in lipid-facing hydrophobic pockets of the transmembrane domain. Our structural analysis suggests that CHS stabilizes PIP₂ interaction with the channel and promotes engagement of the cytoplasmic domain onto the transmembrane region. Mutagenesis of one of the CHS binding pockets eliminates cholesterol-dependent potentiation of GIRK2. Elucidating the structural mechanisms underlying cholesterol modulation of GIRK2 channels could facilitate the development of therapeutics for treating neurological diseases.

Original language	English
Article number	109619
Journal	Cell Reports
Volume	36
Issue number	8
DOIs	https://doi.org/10.1016/j.celrep.2021.109619
State	Published - 24 Aug 2021

Keywords

GIRK
PIP
cholesterol
cryoEM
inwardly rectifying potassium channel
neurodegeneration

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10.1016/j.celrep.2021.109619

Cite this

@article{28574b53df53451492d6753cea2d59fe,

title = "Structural insights into GIRK2 channel modulation by cholesterol and PIP2",

abstract = "G-protein-gated inwardly rectifying potassium (GIRK) channels are important for determining neuronal excitability. In addition to G proteins, GIRK channels are potentiated by membrane cholesterol, which is elevated in the brains of people with neurodegenerative diseases such as Alzheimer's dementia and Parkinson's disease. The structural mechanism of cholesterol modulation of GIRK channels is not well understood. In this study, we present cryo- electron microscopy (cryoEM) structures of GIRK2 in the presence and absence of the cholesterol analog cholesteryl hemisuccinate (CHS) and phosphatidylinositol 4,5-bisphosphate (PIP2). The structures reveal that CHS binds near PIP2 in lipid-facing hydrophobic pockets of the transmembrane domain. Our structural analysis suggests that CHS stabilizes PIP2 interaction with the channel and promotes engagement of the cytoplasmic domain onto the transmembrane region. Mutagenesis of one of the CHS binding pockets eliminates cholesterol-dependent potentiation of GIRK2. Elucidating the structural mechanisms underlying cholesterol modulation of GIRK2 channels could facilitate the development of therapeutics for treating neurological diseases.",

keywords = "GIRK, PIP, cholesterol, cryoEM, inwardly rectifying potassium channel, neurodegeneration",

author = "Mathiharan, {Yamuna Kalyani} and Glaaser, {Ian W.} and Yulin Zhao and Robertson, {Michael J.} and Georgios Skiniotis and Slesinger, {Paul A.}",

note = "Funding Information: An earlier version of this manuscript was uploaded on bioRxiv ( Mathiharan et al., 2020 ). This work was supported in part by the National Institute on Alcohol Abuse and Alcoholism ( AA018734 ) to P.A.S. The cryoEM data for this study were collected at the Stanford-SLAC cryoEM facility. We thank the Slesinger and Skiniotis laboratories for discussions on the experiments, and E. Montabana for help with cryoEM data collection. Some illustrations were created with BioRender.com Publisher Copyright: {\textcopyright} 2021 The Authors",

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AU - Mathiharan, Yamuna Kalyani

AU - Glaaser, Ian W.

AU - Zhao, Yulin

AU - Robertson, Michael J.

AU - Skiniotis, Georgios

AU - Slesinger, Paul A.

N1 - Funding Information: An earlier version of this manuscript was uploaded on bioRxiv ( Mathiharan et al., 2020 ). This work was supported in part by the National Institute on Alcohol Abuse and Alcoholism ( AA018734 ) to P.A.S. The cryoEM data for this study were collected at the Stanford-SLAC cryoEM facility. We thank the Slesinger and Skiniotis laboratories for discussions on the experiments, and E. Montabana for help with cryoEM data collection. Some illustrations were created with BioRender.com Publisher Copyright: © 2021 The Authors

PY - 2021/8/24

Y1 - 2021/8/24

N2 - G-protein-gated inwardly rectifying potassium (GIRK) channels are important for determining neuronal excitability. In addition to G proteins, GIRK channels are potentiated by membrane cholesterol, which is elevated in the brains of people with neurodegenerative diseases such as Alzheimer's dementia and Parkinson's disease. The structural mechanism of cholesterol modulation of GIRK channels is not well understood. In this study, we present cryo- electron microscopy (cryoEM) structures of GIRK2 in the presence and absence of the cholesterol analog cholesteryl hemisuccinate (CHS) and phosphatidylinositol 4,5-bisphosphate (PIP2). The structures reveal that CHS binds near PIP2 in lipid-facing hydrophobic pockets of the transmembrane domain. Our structural analysis suggests that CHS stabilizes PIP2 interaction with the channel and promotes engagement of the cytoplasmic domain onto the transmembrane region. Mutagenesis of one of the CHS binding pockets eliminates cholesterol-dependent potentiation of GIRK2. Elucidating the structural mechanisms underlying cholesterol modulation of GIRK2 channels could facilitate the development of therapeutics for treating neurological diseases.

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