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Title: Structure of a eukaryotic SWEET transporter in a homotrimeric complex

Journal Article · · Nature (London)
DOI:https://doi.org/10.1038/nature15391· OSTI ID:1226370
 [1];  [2];  [3];  [2];  [2];  [1];  [4];  [2];  [1]
  1. Stanford Univ., CA (United States). School of Medicine. Dept. of Molecular and Cellular Physiology
  2. Carnegie Inst. of Science, Stanford, CA (United States). Dept. of Plant Biology
  3. Stanford Univ., CA (United States). School of Medicine. Dept. of Molecular and Cellular Physiology; Sichuan Univ., Chengdu (China). College of Life Sciences. Key Lab. of Bio-Resource and Eco-Environment of Ministry of Education. Center of Growth, Metabolism and Aging
  4. Argonne National Lab. (ANL), Argonne, IL (United States). NE-CAT. Dept. of Chemistry and Chemical Biology

Eukaryotes rely on efficient distribution of energy and carbon skeletons between organs in the form of sugars. Glucose in animals and sucrose in plants serve as the dominant distribution forms. Cellular sugar uptake and release require vesicular and/or plasma membrane transport proteins. Humans and plants use proteins from three superfamilies for sugar translocation: the major facilitator superfamily (MFS), the sodium solute symporter family (SSF; only in the animal kingdom), and SWEETs. SWEETs carry mono- and disaccharides across vacuolar or plasma membranes. Plant SWEETs play key roles in sugar translocation between compartments, cells, and organs, notably in nectar secretion, phloem loading for long distance translocation, pollen nutrition, and seed filling. Plant SWEETs cause pathogen susceptibility possibly by sugar leakage from infected cells. The vacuolar Arabidopsis thaliana AtSWEET2 sequesters sugars in root vacuoles; loss-of-function mutants show increased susceptibility to Pythium infection. In this paper, we show that its orthologue, the vacuolar glucose transporter OsSWEET2b from rice (Oryza sativa), consists of an asymmetrical pair of triple-helix bundles, connected by an inversion linker transmembrane helix (TM4) to create the translocation pathway. Structural and biochemical analyses show OsSWEET2b in an apparent inward (cytosolic) open state forming homomeric trimers. TM4 tightly interacts with the first triple-helix bundle within a protomer and mediates key contacts among protomers. Structure-guided mutagenesis of the close paralogue SWEET1 from Arabidopsis identified key residues in substrate translocation and protomer crosstalk. Finally, insights into the structure–function relationship of SWEETs are valuable for understanding the transport mechanism of eukaryotic SWEETs and may be useful for engineering sugar flux.

Research Organization:
Stanford Univ., CA (United States); Carnegie Inst. of Science, Stanford, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); National Inst. of Health (NIH) (United States); Stanford Univ. (United States); Harold and Leila Y. Mathers Charitable Foundation (United States); Alfred P. Sloan Foundation (United States); National Natural Science Foundation of China (NSFC)
Contributing Organization:
Sichuan Univ., Chengdu (China); Argonne National Lab. (ANL), Argonne, IL (United States)
Grant/Contract Number:
FG02-04ER15542; AC02-06CH11357; IOS-1258018; 1401855; P41 GM103403; 31300618
OSTI ID:
1226370
Journal Information:
Nature (London), Vol. 527, Issue 7577; ISSN 0028-0836
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
ENGLISH
Citation Metrics:
Cited by: 119 works
Citation information provided by
Web of Science

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Cited By (32)

Cotton fiber elongation requires the transcription factor Gh MYB 212 to regulate sucrose transportation into expanding fibers journal January 2019
Variation of a major facilitator superfamily gene contributes to differential cadmium accumulation between rice subspecies journal June 2019
Structural basis for pH-dependent retrieval of ER proteins from the Golgi by the KDEL receptor journal March 2019
New insights into the evolution and functional divergence of the SWEET family in Saccharum based on comparative genomics journal November 2018
The Evolution of Silicon Transport in Eukaryotes. text January 2016
The Arabidopsis vacuolar sugar transporter SWEET2 limits carbon sequestration from roots and restricts Pythium infection journal September 2015
A Medicago truncatula SWEET transporter implicated in arbuscule maintenance during arbuscular mycorrhizal symbiosis journal June 2019
Integrative View of the Diversity and Evolution of SWEET and SemiSWEET Sugar Transporters journal December 2017
Cloning and Functional Assessments of Floral-Expressed SWEET Transporter Genes from Jasminum sambac journal August 2019
Midrib Sucrose Accumulation and Sugar Transporter Gene Expression in YCS-Affected Sugarcane Leaves journal June 2019
Arbuscular mycorrhiza Symbiosis Induces a Major Transcriptional Reprogramming of the Potato SWEET Sugar Transporter Family journal April 2016
Expression in Sf9 insect cells, purification and functional reconstitution of the human proton-coupled folate transporter (PCFT, SLC46A1) journal May 2017
New Insight Into the Diversity of SemiSWEET Sugar Transporters and the Homologs in Prokaryotes journal May 2018
Shared dynamics of LeuT superfamily members and allosteric differentiation by structural irregularities and multimerization journal May 2018
Deciphering evolutionary dynamics of SWEET genes in diverse plant lineages journal September 2018
Structure, evolution and diverse physiological roles of SWEET sugar transporters in plants journal April 2019
Seed filling in domesticated maize and rice depends on SWEET-mediated hexose transport journal November 2015
Molecular Characterization of LjSWEET3, a Sugar Transporter in Nodules of Lotus japonicus journal December 2016
The Expanded SWEET Gene Family Following Whole Genome Triplication in Brassica rapa journal September 2019
B1.12: a novel peptide interacting with the extracellular loop of the EBV oncoprotein LMP1 journal March 2019
Regulation of Amino Acid Transport in Saccharomyces cerevisiae journal October 2019
Arbuscular mycorrhiza symbiosis induces a major transcriptional reprogramming of the potato SWEET sugar transporter family text January 2016
Further studies on sugar transporter (SWEET) genes in wheat (Triticum aestivum L.) journal March 2019
Transcriptome and metabolome reveal redirection of flavonoids in a white testa peanut mutant preprint December 2019
Cutting in the middleman: hidden substrates at the interface between proteases and plant development journal March 2017
Transcriptome and metabolome reveal redirection of flavonoids in a white testa peanut mutant journal November 2019
The Evolution of Silicon Transport in Eukaryotes journal October 2016
Structure of eukaryotic purine/H+ symporter UapA suggests a role for homodimerization in transport activity journal April 2016
GLUT, SGLT, and SWEET: Structural and mechanistic investigations of the glucose transporters: Structural Investigations of the Glucose Transporters journal January 2016
Transcriptome and metabolome reveal redirection of flavonoids in a white testa peanut mutant journal April 2020
DsSWEET17, a Tonoplast-Localized Sugar Transporter from Dianthus spiculifolius, Affects Sugar Metabolism and Confers Multiple Stress Tolerance in Arabidopsis journal May 2018
A genome-wide analysis of SWEET gene family in cotton and their expressions under different stresses journal August 2018

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