@article{07dc4ef99663437d8991357aa0f3c24c,
title = "LLG2/3 Are Co-receptors in BUPS/ANX-RALF Signaling to Regulate Arabidopsis Pollen Tube Integrity",
abstract = "In angiosperms, two sperm cells are transported and delivered by the pollen tube to the ovule to achieve double fertilization. Extensive communication takes place between the pollen tube and the female tissues until the sperm cell cargo is ultimately released. During this process, a pollen tube surface-located receptor complex composed of ANXUR1/2 (ANX1/2) and Buddha's Paper Seal 1/2 (BUPS1/2) was reported to control the maintenance of pollen tube integrity by perceiving the autocrine peptide ligands rapid alkalinization factor 4 and 19 (RALF4/19). It was further hypothesized that pollen-tube rupture to release sperm is caused by the paracrine RALF34 peptide from the ovule interfering with this signaling pathway. In this study, we identified two Arabidopsis pollen-tube-expressed glycosylphosphatidylinositol-anchored proteins (GPI-APs), LORELEI-like-GPI-anchored protein 2 (LLG2) and LLG3, as co-receptors in the BUPS-ANX receptor complex. llg2 llg3 double mutants exhibit severe fertility defects. Mutant pollen tubes rupture early during the pollination process. Furthermore, LLG2 and LLG3 interact with ectodomains of both BUPSs and ANXURs, and this interaction is remarkably enhanced by the presence of RALF4/19 peptides. We further demonstrate that the N terminus (including a YISY motif) of the RALF4 peptide ligand interacts strongly with BUPS-ANX receptors but weakly with LLGs and is essential for its biological function, and its C-terminal region is sufficient for LLG binding. In conclusion, we propose that LLG2/3 serve as co-receptors during BUPS/ANX-RALF signaling and thereby further establish the importance of GPI-APs as key regulators in plant reproduction processes.",
keywords = "Arabidopsis, GPI-AP, RALF, RAPID ALKALINIZATION FACTOR, glycosylphosphatidylinositol-anchored protein, pollen tube, receptor-like kinase, signaling",
author = "Zengxiang Ge and Yuling Zhao and Liu, {Ming Che} and Zhou, {Liang Zi} and Lele Wang and Sheng Zhong and Saiying Hou and Jiahao Jiang and Tianxu Liu and Qingpei Huang and Junyu Xiao and Hongya Gu and Wu, {Hen Ming} and Juan Dong and Thomas Dresselhaus and Cheung, {Alice Y.} and Qu, {Li Jia}",
note = "Funding Information: This work is supported by National Natural Science Foundation of China ( 31830004 , 31620103903 , and 31621001 ), China Postdoctoral Science Foundation ( 2018M640020 and 2019T120012 ), US Natural Science Foundation ( IOS-1645854 and MCB-1715764 ), and National Institute of Food and Agriculture , US Department of Agriculture ( MAS00525 ). Financial support of the Qu laboratory by the Peking-Tsinghua Joint Center for Life Sciences and the Dresselhaus lab by the German Research Council DFG via the Collaborative Research Center SFB924 is gratefully acknowledged. L.W. is recipient of a fellowship from the China Scholarship Council . We also thank the Research Coordination Network on Integrative Pollen Biology ( US-NSF MCB0955910 ) for supporting activities that forged this collaboration. Funding Information: This work is supported by National Natural Science Foundation of China (31830004, 31620103903, and 31621001), China Postdoctoral Science Foundation (2018M640020 and 2019T120012), US Natural Science Foundation (IOS-1645854 and MCB-1715764), and National Institute of Food and Agriculture, US Department of Agriculture (MAS00525). Financial support of the Qu laboratory by the Peking-Tsinghua Joint Center for Life Sciences and the Dresselhaus lab by the German Research Council DFG via the Collaborative Research Center SFB924 is gratefully acknowledged. L.W. is recipient of a fellowship from the China Scholarship Council. We also thank the Research Coordination Network on Integrative Pollen Biology (US-NSF MCB0955910) for supporting activities that forged this collaboration. Conceptualization, L.-J.Q. Z.G. T.D. and A.Y.C.; Investigation, Z.G. Y.Z. L.-Z.Z. A.Y.C. H.-M.W. M.-C.L. L.W. Q.H. S.H. J.J. and T.L.; Writing – Original Draft, L.-J.Q. Z.G. and Y.Z.; Writing – Review & Editing, L.-J.Q. A.Y.C. T.D. J.D. H.-M.W. H.G. J.X. and S.Z.; Funding Acquisition, L.-J.Q. Z.G. T.D. L.W. and A.Y.C.; Resources, Q.H.; Supervision, L.-J.Q. T.D. H.-M.W. and A.Y.C. The authors declare no competing interests. Publisher Copyright: {\textcopyright} 2019 Elsevier Ltd",
year = "2019",
month = oct,
day = "7",
doi = "10.1016/j.cub.2019.08.032",
language = "English (US)",
volume = "29",
pages = "3256--3265.e5",
journal = "Current Biology",
issn = "0960-9822",
publisher = "Cell Press",
number = "19",
}