A small molecule inhibitor partitions two distinct pathways for trafficking of tonoplast intrinsic proteins in Arabidopsis
Tonoplast intrinsic proteins (TIPs) facilitate the membrane transport of water and other small molecules across the plant vacuolar membrane, and members of this family are expressed in specific developmental stages and tissue types. Delivery of TIP proteins to the tonoplast is thought to occur by ve...
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Published in | PloS one Vol. 7; no. 9; p. e44735 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
Public Library of Science
05.09.2012
Public Library of Science (PLoS) |
Subjects | |
Online Access | Get full text |
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Summary: | Tonoplast intrinsic proteins (TIPs) facilitate the membrane transport of water and other small molecules across the plant vacuolar membrane, and members of this family are expressed in specific developmental stages and tissue types. Delivery of TIP proteins to the tonoplast is thought to occur by vesicle-mediated traffic from the endoplasmic reticulum to the vacuole, and at least two pathways have been proposed, one that is Golgi-dependent and another that is Golgi-independent. However, the mechanisms for trafficking of vacuolar membrane proteins to the tonoplast remain poorly understood. Here we describe a chemical genetic approach to unravel the mechanisms of TIP protein targeting to the vacuole in Arabidopsis seedlings. We show that members of the TIP family are targeted to the vacuole via at least two distinct pathways, and we characterize the bioactivity of a novel inhibitor that can differentiate between them. We demonstrate that, unlike for TIP1;1, trafficking of markers for TIP3;1 and TIP2;1 is insensitive to Brefeldin A in Arabidopsis hypocotyls. Using a chemical inhibitor that may target this BFA-insensitive pathway for membrane proteins, we show that inhibition of this pathway results in impaired root hair growth and enhanced vacuolar targeting of the auxin efflux carrier PIN2 in the dark. Our results indicate that the vacuolar targeting of PIN2 and the BFA-insensitive pathway for tonoplast proteins may be mediated in part by common mechanisms. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Competing Interests: The authors have declared that no competing interests exist. Conceived and designed the experiments: MRP. Performed the experiments: MRP ERS MRW. Analyzed the data: MRP ERS MFR. Contributed reagents/materials/analysis tools: GRH. Wrote the paper: MRP. |
ISSN: | 1932-6203 1932-6203 |
DOI: | 10.1371/journal.pone.0044735 |