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Title: The Arabidopsis SWEET1 and SWEET2 uniporters recognize similar substrates while differing in subcellular localization
Sugars Will Eventually be Exported Transporters (SWEETs) are central for sugar allocation in plants. The SWEET family has approximately 20 homologs in most plant genomes, and despite extensive research on their structures and molecular functions, it is still unclear how diverse SWEETs recognize different substrates. Previous work using SweetTrac1, a biosensor constructed by the intramolecular fusion of a conformation-sensitive fluorescent protein in the plasma membrane transporter SWEET1 from Arabidopsis thaliana, identified common features in the transporter’s substrates. Here, we report SweetTrac2, a new biosensor based on the Arabidopsis vacuole membrane transporter SWEET2, and use it to explore the substrate specificity of this second protein. Our results show that SWEET1 and SWEET2 recognize similar substrates but some with different affinities. Sequence comparison and mutagenesis analysis support the conclusion that the differences in affinity depend on nonspecific interactions involving previously uncharacterized residues in the substrate-binding pocket. Furthermore, SweetTrac2 can be an effective tool for monitoring sugar transport at vacuolar membranes that would be otherwise challenging to study.  more » « less
Award ID(s):
1942722
NSF-PAR ID:
10477268
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Journal of Biological Chemistry
Date Published:
Journal Name:
Journal of Biological Chemistry
Volume:
299
Issue:
12
ISSN:
0021-9258
Page Range / eLocation ID:
105389
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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