TMK-PIN1 drives a short self-organizing circuit forauxin export and signaling in Arabidopsis by Rongfeng Huang & Jiacheng Wang & Mingzeng Chang & Wenxin Tang & Yongqiang Yu & Yi Zhang & Yao Peng & Yanan Wang & Yihan Guo & Ting Lu & Yang Cao & Yewei Zhou & Qinglin Zhang & Yuehong Huang & Angxiao Wu & Luyan Ren & Michelle Gallei & Juan Dong &… instant download

TMK-PIN1 drives a short self-organizing circuit forauxin export and signaling in Arabidopsis by Rongfeng Huang & Jiacheng Wang & Mingzeng Chang & Wenxin Tang & Yongqiang Yu & Yi Zhang & Yao Peng & Yanan Wang & Yihan Guo & Ting Lu & Yang Cao & Yewei Zhou & Qinglin Zhang & Yuehong Huang & Angxiao Wu & Luyan Ren & Michelle Gallei & Juan Dong &… instant download

SUMMARYThe versatile and pivotal roles of the phytohormone auxin in regulating plant growth and development are typically linked to its directional transport, relying on the polarized PIN-FORMED (PIN) auxin exporters at theplasma membrane (PM). For decades, auxin has been proposed to promote PIN polarization, generatingself-regulatory feedback mediating much of plant development, but mechanistic insight into this regulationis lacking. Here, we uncover an auxin-induced protein complex at the PM, containing auxin co-receptors transmembrane kinases (TMKs) and PIN1 auxin exporter, as the core machinery that underlies this feedback regulation. Auxin promotes PIN1 phosphorylation by TMKs, modulating PIN1 polarization and transport activity. Wealso provide evidence that PIN1-exported extracellular auxin is crucial for TMK activation and cell elongation,thus forming the simplest two-element self-regulatory feedback circuit. Thus, these findings offer direct mechanistic insights into a potential self-organizing circuit for auxin signaling and transport to ensure proper plantdevelopment in Arabidopsis.