Geldner Niko, Anders Nadine, Wolters Hanno, Keicher Jutta, Kornberger Wolfgang, Muller Philippe, Delbarre Alain, Ueda Takashi, Nakano Akihiko, Jürgens Gerd
ZMBP, Entwicklungsgenetik, Universität Tübingen, Auf der Morgenstelle 3, D-72076, Tübingen, Germany.
Cell. 2003 Jan 24;112(2):219-30. doi: 10.1016/s0092-8674(03)00003-5.
Exchange factors for ARF GTPases (ARF-GEFs) regulate vesicle trafficking in a variety of organisms. The Arabidopsis protein GNOM is a brefeldin A (BFA) sensitive ARF-GEF that is required for the proper polar localization of PIN1, a candidate transporter of the plant hormone auxin. Mutations in GNOM lead to developmental defects that resemble those caused by interfering with auxin transport. Both PIN1 localization and auxin transport are also sensitive to BFA. In this paper, we show that GNOM localizes to endosomes and is required for their structural integrity. We engineered a BFA-resistant version of GNOM. In plants harboring this fully functional GNOM variant, PIN1 localization and auxin transport are no longer sensitive to BFA, while trafficking of other proteins is still affected by the drug. Our results demonstrate that GNOM is required for the recycling of auxin transport components and suggest that ARF-GEFs regulate specific endosomal trafficking pathways.
ARF 鸟苷三磷酸酶交换因子（ARF-GEFs）在多种生物体中调节囊泡运输。拟南芥蛋白 GNOM 是一种对布雷菲德菌素 A（BFA）敏感的 ARF-GEF，它是植物激素生长素的候选转运蛋白 PIN1 正确极性定位所必需的。GNOM 中的突变会导致发育缺陷，类似于干扰生长素运输所引起的缺陷。PIN1 的定位和生长素运输对 BFA 也很敏感。在本文中，我们表明 GNOM 定位于内涵体，并且是其结构完整性所必需的。我们构建了一个对 BFA 具有抗性的 GNOM 版本。在含有这种功能完全正常的 GNOM 变体的植物中，PIN1 的定位和生长素运输对 BFA 不再敏感，而其他蛋白质的运输仍然受到该药物的影响。我们的结果表明，GNOM 是生长素运输成分循环所必需的，并表明 ARF-GEFs 调节特定的内涵体运输途径。
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