title: Arabidopsis TOL proteins act as gatekeepers for vacuolar sorting of PIN2 plasma membrane protein.
abstract: Controlling variations in plasma membrane (PM) protein abundance is of utmost importance for development in higher plants. For modulating PM protein activity, endocytosed proteins can be either cycled between PM and endosomes or sorted for their irreversible inactivation to lysosomes/vacuoles. Cargo ubiquitination triggers vacuolar delivery for degradation, which is controlled by Endosomal Sorting Complex Required for Transport (ESCRT). Essential parts of this machinery are conserved across kingdoms, but determinants liable for initial recognition and concentration of ubiquitinated cargo have not been identified in plants. Here, we describe members of an Arabidopsis TOL (TOM1-LIKE) family as ubiquitin binding proteins that act redundantly in control of plant morphogenesis. Specifically, tol mutant combinations exhibit defects that reflect alterations in responses mediated by the phytohormone auxin. Consistently, we provide evidence for a role of TOLs in recognition and further endocytic sorting of a PIN-FORMED (PIN)-type auxin carrier protein at the PM, modulating dynamic auxin distribution and associated growth responses. Such TOL-dependent vacuolar sorting depends on cargo ubiquitination and coincides with dynamic rearrangements in TOL distribution. Collectively, these findings lead us to suggest a function for TOLs early in the passage of endocytosed ubiquitinated PM cargo, acting as gatekeepers for degradative protein sorting to the vacuole.
authors: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria. Electronic address: barbara.korbei@boku.ac.at.
authors: Barbara
authors: B
authors: Korbei
authors: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria.
authors: Jeanette
authors: J
authors: Moulinier-Anzola
authors: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria.
authors: Lucinda
authors: L
authors: De-Araujo
authors: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria.
authors: Doris
authors: D
authors: Lucyshyn
authors: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria.
authors: Katarzyna
authors: K
authors: Retzer
authors: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria.
authors: Muhammad A
authors: MA
authors: Khan
authors: Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 18, 1190 Wien, Austria. Electronic address: christian.luschnig@boku.ac.at.
authors: Christian
authors: C
authors: Luschnig
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D021381:Protein Transport; D014617:Vacuoles / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C117013:AT5G57090 protein, Arabidopsis