NIK receptor kinases propagate phytocytokine-triggered immunity by driving early phosphorylation events.

All six NIK receptor kinases in Arabidopsis contribute redundantly but distinctly to phytocytokine-triggered immunity, with ligand-dependent phosphorylation essential for immune signaling.

• Why it matters: Understanding how phytocytokine receptor complexes are assembled and activated is crucial for revealing plant immune mechanisms, yet this process remains poorly understood.
• What they did: Researchers examined the NIK family’s role in immune responses triggered by Peps and SCOOP12, analyzing their interactions, phosphorylation, and functional importance through genetic and biochemical approaches.
• The result: NIKs associate with phytocytokine receptors and co-receptors, undergo ligand-dependent phosphorylation, and are essential for full receptor complex activation, BIK1 recruitment, and immune signaling, with Ser615 and Tyr618 being critical residues.