Fig. 7

GRK3 recruits β-arrestin to the C-terminus of S1PR1 and affects S1PR1 internalization. (A) HTLA cells transfected with S1PR1-TCS-tTA receptor construct and empty vector (negative control), GRK2 (positive control), or GRK3 plasmids and stimulated with 1 µM S1P for detection of β-arrestin recruitment response via luminescence. Data represent mean ± SEM, n = 6. (B) Sphingosine-1-phosphate receptor 1 (S1PR1) surface expression as measured by median fluorescence intensity compared to unstimulated cells (0 min) by flow cytometry. WT and Grk3-/- BmMSCs were stimulated with 1 µM S1P at designated timepoints. Data represent mean ± SEM, n = 5, passages 11, 12, 13. *P ≤ 0.05 **P ≤ 0.01 ***P ≤ 0.001 ****P ≤ 0.0001