Biology subjects

Okuda, S.

Publications and source records attributed to Okuda, S..

2 recordsLinked to original sources

bioRxiv2019

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

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.

plant biology↗

bioRxiv2019

Cryo-EM structure of the human L-type amino acid transporter 1 in complex with glycoprotein CD98hc

The L-type amino acid transporter 1 (LAT1) transports large neutral amino acids and drugs across the plasma membrane and is crucial for nutrient uptake, brain drug delivery and tumor growth. LAT1 is a unique solute carrier that forms a disulfide-linked heterodimer with the cell-surface glycoprotein CD98 heavy chain (CD98hc), but the mechanisms of its molecular assembly and amino acid transport are poorly understood. Here we report the cryo-EM structure of the human LAT1-CD98hc heterodimer at 3.4 [A] resolution, revealing the hitherto unprecedented architecture of a solute carrier-glycoprotein heterocomplex. LAT1 features a canonical LeuT-fold while exhibiting an unusual loop structure on transmembrane helix 6, creating an extended cavity to accommodate bulky hydrophobic amino acids and drugs. CD98hc engages with LAT1 through multiple interactions, not only in the extracellular and transmembrane domains but also in the interdomain linker. The heterodimer interface features multiple sterol molecules, corroborating previous biochemical data on the role of cholesterols in heterodimer stabilization. We also visualized the binding modes of two anti-CD98 antibodies and show that they recognize distinct, multiple epitopes on CD98hc but not its glycans, explaining their robust reactivities despite the glycan heterogeneity. Furthermore, we mapped disease-causing mutations onto the structure and homology models, which rationalized some of the phenotypes of SLC3- and SLC7-related congenital disorders. Together, these results shed light on the principles of the structural assembly between a glycoprotein and a solute carrier, and provide a template for improving preclinical drugs and therapeutic antibodies targeting LAT1 and CD98.

biochemistry↗