Abstract
Transport of Golgi-localized proteins from the ER is mediated by the coat protein complex II (COPII) and its members, COPII inner coat subunit Sec24 and Secretion-associated Ras-related GTPase 1 (Sar1). Sar1 and Sec24 recognize cytosolic N-termini of glycosyltransferases (GTs) that contain peptide signals required for incorporation into COPII-coated vesicles. Xyloglucan Xylosyltransferases (XXTs) are required for xyloglucan (XyGs) biosynthesis and must be transported to the Golgi for proper function. In this study, we demonstrated that XXTs interact with AtSar1 in the COPII complex but not with AtSec24, which was previously reported to be the main recruiter of cargo proteins into COPII-coated vesicles. The mutation of the arginine to glutamine residues of di-arginine motifs in the N-termini of XXTs caused protein mislocalization and significantly reduced the strength of the interaction with AtSar1. These mutations caused 90% of XXTs to either remain in the ER or localize to small non-Golgi compartments. In turn, such mislocalization significantly suppressed the recovery of XyGs biosynthesis in Arabidopsis thaliana (Arabidopsis) mutants (xxt1xxt2 and xxt3xxt4xxt5), failing to restore their root phenotypes to normal. Our results demonstrate the interaction between cargo and AtSar1, highlighting the critical role of di-arginine motifs in this interaction. These results provide new insights into the mechanism of ER-to-Golgi delivery of plant GTs, which significantly advances our understanding of polysaccharide biosynthesis in the Golgi and the enzymes responsible for it.
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Claims 8
Claim · model-written summary
XXTs interact with AtSar1 in the COPII complex.
- Taxon
- Arabidopsis
Arabidopsist0 - Gene
- XXTse0
- Outcome
- interact with AtSar1e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“XXTs interact with AtSar1 in the COPII complex but not with AtSec24”
Claim · model-written summary
XXTs do not interact with AtSec24.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- AtSec24e0
- Outcome
- not with AtSec24e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“XXTs interact with AtSar1 in the COPII complex but not with AtSec24”
Claim · model-written summary
Mutating arginine to glutamine in the di-arginine motifs of the XXT N-termini caused protein mislocalization.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mutation of the arginine to glutamine residues of di-arginine motifse0
- Gene
- XXTse0
- Outcome
- protein mislocalizatione1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“The mutation of the arginine to glutamine residues of di-arginine motifs in the N-termini of XXTs”
e1“caused protein mislocalization”
Claim · model-written summary
The arginine-to-glutamine mutation in XXT N-termini significantly reduced the strength of the interaction with AtSar1.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mutation of the arginine to glutamine residues of di-arginine motifse0
- Gene
- XXTse0
- Outcome
- strength of the interaction with AtSar1e1
- Direction
- reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“The mutation of the arginine to glutamine residues of di-arginine motifs in the N-termini of XXTs”
e1“significantly reduced the strength of the interaction with AtSar1”
Claim · model-written summary
The mutations caused 90% of XXTs to remain in the ER or localize to small non-Golgi compartments.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mutationse0
- Gene
- XXTse0
- Outcome
- remain in the ER or localize to small non-Golgi compartmentse0
- Value
- 90%e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“These mutations caused 90% of XXTs to either remain in the ER or localize to small non-Golgi compartments”
Claim · model-written summary
Mislocalization of the mutated XXTs significantly suppressed recovery of xyloglucan biosynthesis in the xxt1xxt2 and xxt3xxt4xxt5 mutants.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae0
- Material
- xxt1xxt2 and xxt3xxt4xxt5e0
- Treatment
- mislocalizatione0
- Outcome
- recovery of XyGs biosynthesise0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“such mislocalization significantly suppressed the recovery of XyGs biosynthesis in Arabidopsis thaliana (Arabidopsis) mutants (xxt1xxt2 and xxt3xxt4xxt5)”
Claim · model-written summary
The mislocalized XXTs failed to restore the root phenotypes of the mutants to normal.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mislocalizatione0
- Outcome
- root phenotypese1
- Direction
- failing to restoree1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“such mislocalization significantly suppressed”
e1“failing to restore their root phenotypes to normal”
Claim · model-written summary
The authors conclude that di-arginine motifs play a critical role in the cargo-AtSar1 interaction.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- interactione0
- Qualifier
- critical role of di-arginine motifse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis”
e0“the critical role of di-arginine motifs in this interaction”