HSL1 and BAM1/2 impact epidermal cell development by sensing distinct signaling peptides

• Published in: Nature communications Vol. 13; no. 1; pp. 876 - 13
• Main Authors: Roman, Andra-Octavia, Jimenez-Sandoval, Pedro, Augustin, Sebastian, Broyart, Caroline, Hothorn, Ludwig A., Santiago, Julia
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.02.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 14/19; 631/449/2675; 631/45/535/1266; 82/103; 82/16; 82/80; 9/10; 96/95; Affinity; Animals; Arabidopsis; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell division; Cell Line; Crystal structure; Epidermal Cells - cytology; Homeostasis; Homology; Humanities and Social Sciences; Intercellular Signaling Peptides and Proteins - metabolism; Intracellular Signaling Peptides and Proteins - metabolism; Kinases; Leaves; multidisciplinary; Nicotiana; Organs; Pattern formation; Peptides; Plant Leaves - embryology; Plant tissues; Protein Kinases - metabolism; Protein Serine-Threonine Kinases - genetics; Protein Serine-Threonine Kinases - metabolism; Receptor mechanisms; Receptors; Repressor Proteins - genetics; Repressor Proteins - metabolism; Science; Science (multidisciplinary); Separation processes; Sf9 Cells; Signaling
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-28558-4

The membrane receptor kinases HAESA and HSL2 recognize a family of IDA/IDL signaling peptides to control cell separation processes in different plant organs. The homologous HSL1 has been reported to regulate epidermal cell patterning by interacting with a different class of signaling peptides from the CLE family. Here we demonstrate that HSL1 binds IDA/IDL peptides with high, and CLE peptides with lower affinity, respectively. Ligand sensing capability and receptor activation of HSL1 require a SERK co-receptor kinase. Crystal structures with IDA/IDLs or with CLE9 reveal that HSL1-SERK1 complex recognizes the entire IDA/IDL signaling peptide, while only parts of CLE9 are bound to the receptor. In contrast, the receptor kinase BAM1 interacts with the entire CLE9 peptide with high affinity and specificity. Furthermore, the receptor tandem BAM1/BAM2 regulates epidermal cell division homeostasis. Consequently, HSL1-IDLs and BAM1/BAM2-CLEs independently regulate cell patterning in the leaf epidermal tissue. HAESA and HSL2 are receptors for IDA/IDL-family signaling peptides in plants. Here the authors show that HSL1, previously shown to recognize CLE9, preferentially binds IDA/IDL peptides and regulates leaf epidermal patterning independently of CLE peptides.