Fig. 4.

Detection of TRPM7 within membranes by biotinylation experiments. a Representative immunoblots showing the detection of TRPM7 and Na⁺/K⁺-ATPase in NT (1), WT-CFTR (2), ΔF508-CFTR (3) and G551D-CFTR (4) cells, in biotinylated surface proteins and in non biotinylated proteins (Eluates). TRPM7 is present in the membrane fraction whereas it is likely not observed in non biotinylated proteins. The lower panel showing the presence of a specific membrane protein (Na⁺/K⁺-ATPase) in the biotinylated fractions indicates that membrane proteins were enriched in the biotinylated fractions. b Bar chart of the densitometric analysis of the cell surface expression of TRPM7 after normalization by Na⁺/K⁺-ATPase. The level of TRPM7 is higher in the membranes of WT-CFTR and ΔF508-CFTR cells than in NT and G551D-CFTR cells