Fig. 3: The N-terminus of LSD1 is disordered and shows phase separation behavior.

a Intrinsic disorder prediction of LSD1 using the PONDR VSL2 algorithm¹⁰⁸. The N-terminal domain (NTD) designates the IDR containing the phosphorylation site under investigation. Additional domains of LSD1 are indicated¹⁰⁹. The X-axis depicts residue numbers plotted against the degree of folding prediction. b CD spectra of the LSD1 IDR-His compared to reference data of secondary structure elements for α-helix and β-sheet¹¹⁰. c Phase separation of purified IDR-mV compared to mV (10 µM). Phase separation was induced by the addition of 20% PEG and reduction of KCl to 10 mM. Top: macroscopic phase separation of IDR-mV. Bottom: fluorescence images showing condensed droplets of IDR-mV compared to mV, Scale bar = 200 µm. d Representative fluorescence microscopy images showing in vitro droplet formation of IDR-mV under different protein concentrations (2, 4, 6 µM). Scale bar = 50 µm. e Representative bright field and fluorescence microscopy images showing in vitro condensation of IDR-mV under different pH conditions. Scale bar = 10 µm. f Representative bright-field microscopy images of phase-separated IDR-mV droplets showing a time course of condensate fusion. Scale bar = 5 µm. g Size analysis of the droplets shown in (f) before and after the fusion event. h Representative fluorescence microscopy images at different time points during FRAP experiments proving protein mobility within droplet. Scale bars = 2 µm. i Representative bright-field microscopy images of in vitro phase separated IDR-mV droplets before and after addition of external salt showing droplet dissolution. Scale bar = 10 µm.