Doyle, Siamsa; Haegera, Ash; Vain, Thomas; Rigala, Adeline; Viotti, Corrado; Łangowskaa, Małgorzata; Maa, Qian; Friml, JiríIST Austria ; Raikhel, Natasha; Hickse, Glenn; Robert, Stéphanie
Spatial regulation of the plant hormone indole-3-acetic acid (IAA, or auxin) is essential for plant development. Auxin gradient establishment is mediated by polarly localized auxin transporters, including PIN-FORMED (PIN) proteins. Their localization and abundance at the plasma membrane are tightly regulated by endomembrane machinery, especially the endocytic and recycling pathways mediated by the ADP ribosylation factor guanine nucleotide exchange factor (ARF-GEF) GNOM. We assessed the role of the early secretory pathway in establishing PIN1 polarity in Arabidopsis thaliana by pharmacological and genetic approaches. We identified the compound endosidin 8 (ES8), which selectively interferes with PIN1 basal polarity without altering the polarity of apical proteins. ES8 alters the auxin distribution pattern in the root and induces a strong developmental phenotype, including reduced root length. The ARF-GEF- defective mutants gnom-like 1 ( gnl1-1) and gnom ( van7) are significantly resistant to ES8. The compound does not affect recycling or vacuolar trafficking of PIN1 but leads to its intracellular accumulation, resulting in loss of PIN1 basal polarity at the plasma membrane. Our data confirm a role for GNOM in endoplasmic reticulum (ER) - Golgi trafficking and reveal that a GNL1/GNOM-mediated early secretory pathway selectively regulates PIN1 basal polarity establishment in a manner essential for normal plant development.
This work was supported by Vetenskapsrådet and Vinnova (Verket för Innovationssystemet) (S.M.D., T.V., M.Ł., and S.R.), Knut och Alice Wallenbergs Stiftelse (S.M.D., A.R., and C.V.), Kempestiftelserna (A.H. and Q.M.), Carl Tryggers Stiftelse för Vetenskaplig Forskning (Q.M.), European Research Council Grant ERC-2011-StG-20101109-PSDP (to J.F.), US Department of Energy Grant DE-FG02-02ER15295 (to N.V.R.), and National Science Foundation Grant MCB-0817916 (to N.V.R. and G.R.H.).
E806 - E815
Doyle S, Haegera A, Vain T, et al. An early secretory pathway mediated by gnom-like 1 and gnom is essential for basal polarity establishment in Arabidopsis thaliana. PNAS. 2015;112(7):E806-E815. doi:10.1073/pnas.1424856112
Doyle, S., Haegera, A., Vain, T., Rigala, A., Viotti, C., Łangowskaa, M., … Robert, S. (2015). An early secretory pathway mediated by gnom-like 1 and gnom is essential for basal polarity establishment in Arabidopsis thaliana. PNAS. National Academy of Sciences. https://doi.org/10.1073/pnas.1424856112
Doyle, Siamsa, Ash Haegera, Thomas Vain, Adeline Rigala, Corrado Viotti, Małgorzata Łangowskaa, Qian Maa, et al. “An Early Secretory Pathway Mediated by Gnom-like 1 and Gnom Is Essential for Basal Polarity Establishment in Arabidopsis Thaliana.” PNAS. National Academy of Sciences, 2015. https://doi.org/10.1073/pnas.1424856112.
S. Doyle et al., “An early secretory pathway mediated by gnom-like 1 and gnom is essential for basal polarity establishment in Arabidopsis thaliana,” PNAS, vol. 112, no. 7. National Academy of Sciences, pp. E806–E815, 2015.
Doyle S, Haegera A, Vain T, Rigala A, Viotti C, Łangowskaa M, Maa Q, Friml J, Raikhel N, Hickse G, Robert S. 2015. An early secretory pathway mediated by gnom-like 1 and gnom is essential for basal polarity establishment in Arabidopsis thaliana. PNAS. 112(7), E806–E815.
Doyle, Siamsa, et al. “An Early Secretory Pathway Mediated by Gnom-like 1 and Gnom Is Essential for Basal Polarity Establishment in Arabidopsis Thaliana.” PNAS, vol. 112, no. 7, National Academy of Sciences, 2015, pp. E806–15, doi:10.1073/pnas.1424856112.
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