Journal: The Journal of Clinical Investigation
Article Title: Polyamine sequestration of 2 ′ 3 ′ -cGAMP constrains intercellular transmission and STING engagement to subvert antitumor immunity
doi: 10.1172/JCI201460
Figure Lengend Snippet: ( A – C ) IB analysis of lysates from mouse PMs were pretreated with different doses of spermine ( A ), spermidine ( B ), or 10 μM polyamines ( C ) for 1 hour, then incubated with 2′3′-cGAMP-biotin for 4 hours, followed by IP with streptavidin. ( D ) IB analysis of STING dimerization in mouse PMs pretreated with spermine or spermidine, followed by transfection with 2′3′-cGAMP. STING dimerization levels were quantitated by measuring dimer-STING band intensities using ImageJ software; the values were normalized to actin (bar chart). ( E and F ) Molecular docking analysis of spermine ( E ) or spermidine ( F ) interactions with 2′3′-cGAMP, c-di-AMP, c-di-GMP, or 3′3′-cGAMP. ( G – J ) Molecular docking of STING protein with 2′3′-cGAMP ( G ) supplemented with spermine ( H ), spermidine ( I ), and putrescine ( J ). ( K ) Representative confocal images of PLA between spermine or spermidine and STING in PMs pretreated with spermine or spermidine and transfected with 2′3′-cGAMP for 1 hour. The assembly of STING with polyamines was quantitated by the fluorescence intensity using ImageJ software (chart). Scale bars, 10 μm. ( L ) Lysates from mouse PMs pretreated with spermine-, spermidine-, or putrescine-biotin and transfected with 2′3′-cGAMP for 2 hours, followed by IP with streptavidin. IB analysis of STING expression. ( M ) Schematic of spermine and spermidine affecting the binding affinity between 2′3′-cGAMP and STING. Images were created with BioRender. Similar results were obtained from 3 independent experiments. Put, putrescine; Spm, spermine; Spd, spermidine; Trans., transfection; US, unstimulated.
Article Snippet: 2′3′-cGAMP (catalog tlrl-nacga23), 3′3′-cGAMP (catalog tlrl-nacga), c-di-AMP (catalog tlrl-nacda), c-di-GMP (catalog tlrl-nacdg), poly(dG:dC) (catalog tlrl-pgcn), and G3-YSD (catalog tlrl-ydna) were purchased from InvivoGen.
Techniques: Incubation, Transfection, Software, Fluorescence, Expressing, Binding Assay