Liang Wang
Postdoctoral Scholar, Molecular and Cellular Physiology
All Publications
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Structural basis of substrate recognition and translocation by human very long-chain fatty acid transporter ABCD1.
Nature communications
2022; 13 (1): 3299
Abstract
Human ABC transporter ABCD1 transports very long-chain fatty acids from cytosol to peroxisome for β-oxidation, dysfunction of which usually causes the X-linked adrenoleukodystrophy (X-ALD). Here, we report three cryogenic electron microscopy structures of ABCD1: the apo-form, substrate- and ATP-bound forms. Distinct from what was seen in the previously reported ABC transporters, the two symmetric molecules of behenoyl coenzyme A (C22:0-CoA) cooperatively bind to the transmembrane domains (TMDs). For each C22:0-CoA, the hydrophilic 3'-phospho-ADP moiety of CoA portion inserts into one TMD, with the succeeding pantothenate and cysteamine moiety crossing the inter-domain cavity, whereas the hydrophobic fatty acyl chain extends to the opposite TMD. Structural analysis combined with biochemical assays illustrates snapshots of ABCD1-mediated substrate transport cycle. It advances our understanding on the selective oxidation of fatty acids and molecular pathology of X-ALD.
View details for DOI 10.1038/s41467-022-30974-5
View details for PubMedID 35676282
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Structure and transport mechanism of the human cholesterol transporter ABCG1
CELL REPORTS
2022; 38 (4): 110298
Abstract
The reverse cholesterol transport pathway is responsible for the maintenance of human cholesterol homeostasis, an imbalance of which usually leads to atherosclerosis. As a key component of this pathway, the ATP-binding cassette transporter ABCG1 forwards cellular cholesterol to the extracellular acceptor nascent high-density lipoprotein (HDL). Here, we report a 3.26-Å cryo-electron microscopy structure of cholesterol-bound ABCG1 in an inward-facing conformation, which represents a turnover condition upon ATP binding. Structural analyses combined with functional assays reveals that a cluster of conserved hydrophobic residues, in addition to two sphingomyelins, constitute a well-defined cholesterol-binding cavity. The exit of this cavity is closed by three pairs of conserved Phe residues, which constitute a hydrophobic path for the release of cholesterol in an acceptor concentration-dependent manner. Overall, we propose an ABCG1-driven cholesterol transport cycle initiated by sphingomyelin-assisted cholesterol recruitment and accomplished by the release of cholesterol to HDL.
View details for DOI 10.1016/j.celrep.2022.110298
View details for Web of Science ID 000750976000008
View details for PubMedID 35081353
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Structures of human bile acid exporter ABCB11 reveal a transport mechanism facilitated by two tandem substrate-binding pockets
CELL RESEARCH
2022; 32 (5): 501-504
View details for DOI 10.1038/s41422-021-00611-9
View details for Web of Science ID 000743886500001
View details for PubMedID 35043010
View details for PubMedCentralID PMC9061823
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A gain-of-function mutation of the MATE family transporter DTX6 confers paraquat resistance in Arabidopsis
MOLECULAR PLANT
2021; 14 (12): 2126-2133
Abstract
Paraquat is one of the most widely used nonselective herbicides and has elicited the emergence of paraquat-resistant weeds. However, the molecular mechanisms of paraquat resistance are not completely understood. Here we report the Arabidopsis gain-of-function mutant pqt15-D with significantly enhanced resistance to paraquat and the corresponding gene PQT15, which encodes the Multidrug and Toxic Extrusion (MATE) transporter DTX6. A point mutation at +932 bp in DTX6 causes a G311E amino acid substitution, enhancing the paraquat resistance of pqt15-D, and overexpression of DTX6/PQT15 in the wild-type plants also results in strong paraquat resistance. Moreover, heterologous expression of DTX6 and DTX6-D in Escherichia coli significantly enhances bacterial resistance to paraquat. Importantly, overexpression of DTX6-D enables Arabidopsis plants to tolerate 4 mM paraquat, a near-commercial application level. DTX6/PQT15 is localized in the plasma membrane and endomembrane, and functions as a paraquat efflux transporter as demonstrated by paraquat efflux assays with isolated protoplasts and bacterial cells. Taken together, our results demonstrate that DTX6/PQT15 is an efflux transporter that confers paraquat resistance by exporting paraquat out of the cytosol. These findings reveal a molecular mechanism of paraquat resistance in higher plants and provide a promising candidate gene for engineering paraquat-resistant crops.
View details for DOI 10.1016/j.molp.2021.09.004
View details for Web of Science ID 000729175700017
View details for PubMedID 34509638
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Structures of cyanobacterial bicarbonate transporter SbtA and its complex with PII-like SbtB
CELL DISCOVERY
2021; 7 (1): 63
View details for DOI 10.1038/s41421-021-00287-w
View details for Web of Science ID 000685106500003
View details for PubMedID 34373447
View details for PubMedCentralID PMC8352866
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Cryo-EM structure of human bile salts exporter ABCB11
CELL RESEARCH
2020; 30 (7): 623-625
View details for DOI 10.1038/s41422-020-0302-0
View details for Web of Science ID 000520828000001
View details for PubMedID 32203132
View details for PubMedCentralID PMC7343855
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Cryo-EM structure of human lysosomal cobalamin exporter ABCD4
CELL RESEARCH
2019; 29 (12): 1039-1041
View details for DOI 10.1038/s41422-019-0222-z
View details for Web of Science ID 000500749600010
View details for PubMedID 31467407
View details for PubMedCentralID PMC6951267