Lipid interaction triggering Septin2 to assembly into β-sheet structures investigated by Langmuir monolayers and PM-IRRAS

► Investigation of the binding of SEPT2 to PtdIns(4,5)P2 and DPPC, using the Langmuir monolayer, DSC and PM-IRRAS techniques ► SEPT2 interacts with PtdIns(4,5)P2, remaining incorporated in the monolayer and with its secondary structure preserved. ► The binding to DPPC could trigger SEPT2 assembly into amyloid fibrils. ► SEPT2 in amyloid filament conformation no longer interacts with PtdIns(4,5)P2 in the Langmuir monolayer.