PT  - JOURNAL ARTICLE
AU  - Xu, Tongda
AU  - Dai, Ning
AU  - Chen, Jisheng
AU  - Nagawa, Shingo
AU  - Cao, Min
AU  - Li, Hongjiang
AU  - Zhou, Zimin
AU  - Chen, Xu
AU  - De Rycke, Riet
AU  - Rakusová, Hana
AU  - Wang, Wuyi
AU  - Jones, Alan M.
AU  - Friml, Jiří
AU  - Patterson, Sara E.
AU  - Bleecker, Anthony B.
AU  - Yang, Zhenbiao
TI  - Cell Surface ABP1-TMK Auxin-Sensing Complex Activates ROP GTPase Signaling
AID  - 10.1126/science.1245125
DP  - 2014 Feb 28
TA  - Science
PG  - 1025--1028
VI  - 343
IP  - 6174
4099  - http://science.sciencemag.org/content/343/6174/1025.short
4100  - http://science.sciencemag.org/content/343/6174/1025.full
SO  - Science2014 Feb 28; 343
AB  - The plant hormone auxin regulates a variety of developmental processes and responses to environmental inputs, often via changes in gene transcription. Xu et al. (p. 1025) analyzed a signaling pathway involving ABP1 (auxin-binding protein 1) that affects the cytoskeleton and endocytosis in Arabidopsis without changing gene transcription. Instead, ABP1 functions at the cell surface to bind auxin and a family of membrane kinases, thereby activating intracellular guanosine triphosphatases to initiate important developmental changes in cell shape. Auxin-binding protein 1 (ABP1) was discovered nearly 40 years ago and was shown to be essential for plant development and morphogenesis, but its mode of action remains unclear. Here, we report that the plasma membrane–localized transmembrane kinase (TMK) receptor–like kinases interact with ABP1 and transduce auxin signal to activate plasma membrane–associated ROPs [Rho-like guanosine triphosphatases (GTPase) from plants], leading to changes in the cytoskeleton and the shape of leaf pavement cells in Arabidopsis. The interaction between ABP1 and TMK at the cell surface is induced by auxin and requires ABP1 sensing of auxin. These findings show that TMK proteins and ABP1 form a cell surface auxin perception complex that activates ROP signaling pathways, regulating nontranscriptional cytoplasmic responses and associated fundamental processes.