title: The Putative O-Linked N-Acetylglucosamine Transferase SPINDLY Inhibits Class I TCP Proteolysis to Promote Sensitivity to Cytokinin.
abstract: Arabidopsis (Arabidopsis thaliana) SPINDLY (SPY) is a putative serine and threonine O-linked N-acetylglucosamine transferase (OGT). While SPY has been shown to suppress gibberellin signaling and to promote cytokinin (CK) responses, its catalytic OGT activity was never demonstrated and its effect on protein fate is not known. We previously showed that SPY interacts physically and functionally with TCP14 and TCP15 to promote CK responses. Here, we aimed to identify how SPY regulates TCP14/15 activities and how these TCPs promote CK responses. We show that SPY activity is required for TCP14 stability. Mutation in the putative OGT domain of SPY (spy-3) stimulated TCP14 proteolysis by the 26S proteasome, which was reversed by mutation in CULLIN1 (CUL1), suggesting a role for SKP, CUL1, F-box E3 ubiquitin ligase in TCP14 proteolysis. TCP14 proteolysis in spy-3 suppressed all TCP14 misexpression phenotypes, including the enhanced CK responses. The increased CK activity in TCP14/15-overexpressing flowers resulted from increased sensitivity to the hormone and not from higher CK levels. TCP15 overexpression enhanced the response of the CK-induced synthetic promoter pTCS to CK, suggesting that TCP14/15 affect early steps in CK signaling. We propose that posttranslational modification of TCP14/15 by SPY inhibits their proteolysis and that the accumulated proteins promote the activity of the CK phosphorelay cascade in developing Arabidopsis leaves and flowers.
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Evyatar
authors.initials: E
authors.lastname: Steiner
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Sivan
authors.initials: S
authors.lastname: Livne
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Tammy
authors.initials: T
authors.lastname: Kobinson-Katz
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Lior
authors.initials: L
authors.lastname: Tal
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Oded
authors.initials: O
authors.lastname: Pri-Tal
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Assaf
authors.identifier: 0000-0003-0467-9287
authors.initials: A
authors.lastname: Mosquna
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Danuše
authors.identifier: 0000-0003-1478-1904
authors.initials: D
authors.lastname: Tarkowská
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Bruno
authors.initials: B
authors.lastname: Mueller
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.).
authors.forename: Petr
authors.initials: P
authors.lastname: Tarkowski
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel (E.S., S.L., T.K.-K., O.P.-T., A.M., D.W.);Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel (L.T.);Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Metabolomics, Institute of Experimental Botany, CZ-78371 Olomouc, Czech Republic (D.T.);Department of Plant and Microbial Biology, University of Zurich, Zurich-Basel Plant Science Center, 8008 Zurich, Switzerland (B.M.); andCentre of the Region Haná for Biotechnological and Agricultural Research, Central Laboratories and Research Support, Faculty of Science, Palacky University, and Department of Genetic Resources for Vegetables, Medicinal, and Special Plants, Crop Research Institute, CZ-78371 Olomouc, Czech Republic (P.T.) david.weiss@mail.huji.ac.il.
authors.forename: David
authors.identifier: 0000-0002-3253-8441
authors.initials: D
authors.lastname: Weiss
mesh_terms: D029681:Arabidopsis Proteins / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D020134:Catalytic Domain; D003583:Cytokinins / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D055550:Protein Stability; D059748:Proteolysis / Q000187:drug effects*; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D003583:Cytokinins; D012097:Repressor Proteins; C101465:SPY protein, Arabidopsis; C581419:TCP14 protein, Arabidopsis; C558187:TCP15 protein, Arabidopsis; D014157:Transcription Factors; D046988:Proteasome Endopeptidase Complex