article published yes Maciek Adamowski author 45F536D2-F248-11E8-B48F-1D18A9856A870000-0001-6463-5257 Ivana Matijevic author 83c17ce3-15b2-11ec-abd3-f486545870bd Jiří Friml author 4159519E-F248-11E8-B48F-1D18A9856A870000-0002-8302-7596 JiFr department Tracing Evolution of Auxin Transport and Polarity in Plants project Molecular mechanisms of endocytic cargo recognition in plants project FWF Open Access Fund project The GNOM (GN) Guanine nucleotide Exchange Factor for ARF small GTPases (ARF-GEF) is among the best studied trafficking regulators in plants, playing crucial and unique developmental roles in patterning and polarity. The current models place GN at the Golgi apparatus (GA), where it mediates secretion/recycling, and at the plasma membrane (PM) presumably contributing to clathrin-mediated endocytosis (CME). The mechanistic basis of the developmental function of GN, distinct from the other ARF-GEFs including its closest homologue GNOM-LIKE1 (GNL1), remains elusive. Insights from this study largely extend the current notions of GN function. We show that GN, but not GNL1, localizes to the cell periphery at long-lived structures distinct from clathrin-coated pits, while CME and secretion proceed normally in <jats:italic>gn</jats:italic> knockouts. The functional GN mutant variant GN<jats:sup>fewerroots</jats:sup>, absent from the GA, suggests that the cell periphery is the major site of GN action responsible for its developmental function. Following inhibition by Brefeldin A, GN, but not GNL1, relocates to the PM likely on exocytic vesicles, suggesting selective molecular associations en route to the cell periphery. A study of GN-GNL1 chimeric ARF-GEFs indicates that all GN domains contribute to the specific GN function in a partially redundant manner. Together, this study offers significant steps toward the elucidation of the mechanism underlying unique cellular and development functions of GNOM. https://research-explorer.ista.ac.at/download/15033/17310/2024_eLife_Adamowski.pdf application/pdfno https://creativecommons.org/licenses/by/4.0/ eLife Sciences Publications2024 eng General Immunology and MicrobiologyGeneral BiochemistryGenetics and Molecular BiologyGeneral MedicineGeneral Neuroscience 2050-084X 38381485 00117427800000110.7554/elife.68993 13 M. Adamowski, I. Matijevic, J. Friml, ELife 13 (2024). Adamowski, Maciek, et al. “Developmental Patterning Function of GNOM ARF-GEF Mediated from the Cell Periphery.” <i>ELife</i>, vol. 13, eLife Sciences Publications, 2024, doi:<a href="https://doi.org/10.7554/elife.68993">10.7554/elife.68993</a>. Adamowski M, Matijevic I, Friml J. 2024. Developmental patterning function of GNOM ARF-GEF mediated from the cell periphery. eLife. 13. Adamowski, M., Matijevic, I., &#38; Friml, J. (2024). Developmental patterning function of GNOM ARF-GEF mediated from the cell periphery. <i>ELife</i>. eLife Sciences Publications. <a href="https://doi.org/10.7554/elife.68993">https://doi.org/10.7554/elife.68993</a> M. Adamowski, I. Matijevic, and J. Friml, “Developmental patterning function of GNOM ARF-GEF mediated from the cell periphery,” <i>eLife</i>, vol. 13. eLife Sciences Publications, 2024. Adamowski, Maciek, Ivana Matijevic, and Jiří Friml. “Developmental Patterning Function of GNOM ARF-GEF Mediated from the Cell Periphery.” <i>ELife</i>. eLife Sciences Publications, 2024. <a href="https://doi.org/10.7554/elife.68993">https://doi.org/10.7554/elife.68993</a>. Adamowski M, Matijevic I, Friml J. Developmental patterning function of GNOM ARF-GEF mediated from the cell periphery. <i>eLife</i>. 2024;13. doi:<a href="https://doi.org/10.7554/elife.68993">10.7554/elife.68993</a> 150332024-02-27T07:10:11Z2025-10-15T06:31:47Z