Molecular mechanism for the recognition of sequence-divergent CIF peptides by the plant receptor kinases GSO1/SGN3 and GSO2.

Okuda, S.; Fujita, S.; Moretti, A.; Hohmann, U.; Gonzalez Doblas, V. G.; Ma, Y.; Pfister, A.; Brandt, B.; Geldner, N.; Hothorn, M.

doi:10.1101/692228

bioRxiv · 10.1101/692228

Molecular mechanism for the recognition of sequence-divergent CIF peptides by the plant receptor kinases GSO1/SGN3 and GSO2.

Okuda, S.·Fujita, S.·Moretti, A.·Hohmann, U.·Gonzalez Doblas, V. G.·Ma, Y.·Pfister, A.·Brandt, B.·Geldner, N.·Hothorn, M.

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Abstract

Plants use leucine-rich repeat receptor kinases (LRR-RKs) to sense sequence diverse peptide hormones at the cell surface. A 3.0 [A] crystal structure of the LRR-RK GSO1/SGN3 regulating Casparian strip formation in the endodermis reveals a large spiral-shaped ectodomain. The domain provides a binding platform for 21 amino-acid CIF peptide ligands, which are tyrosine sulfated by the tyrosylprotein sulfotransferase TPST/SGN2. GSO1/SGN3 harbors a binding pocket for sulfotyrosine and makes extended backbone interactions with CIF2. Quantitative biochemical comparisons reveal that GSO1/SGN3 - CIF2 represents one of the strongest receptor-ligand pairs known in plants. Multiple missense mutations are required to block CIF2 binding in vitro, and GSO1/SGN3 function in vivo. Using structure-guided sequence analysis we uncover novel CIF peptides conserved among higher plants. Quantitative binding assays with known and novel CIFs suggest that the homologous LRR-RKs GSO1/SGN3 and GSO2 have evolved unique peptide binding properties to control different developmental processes. A quantitative biochemical interaction screen, a CIF peptide antagonist and genetic analyses together implicate SERK LRR-RKs as essential co-receptor kinases required for GSO1/SGN3 and GSO2 receptor activation. 0ur work provides a mechanistic framework for the recognition of sequence-divergent peptide hormones in plants.\n\nSignificance StatementTwo sequence-related plant membrane receptor kinases and their shape-complementary co-receptors are shown to selectively sense members of a small family of secreted peptide hormones to control formation of an important diffusion barrier in the plant root.

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Okuda, S., Fujita, S., Moretti, A., Hohmann, U., Gonzalez Doblas, V. G., Ma, Y., Pfister, A., Brandt, B., Geldner, N., Hothorn, M.. 2019-07-04. Molecular mechanism for the recognition of sequence-divergent CIF peptides by the plant receptor kinases GSO1/SGN3 and GSO2.. https://doi.org/10.1101/692228

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