Figure 1. Posttranslational modification of S1P₁ after FTY720P treatment.

(A) Schematic of S1P₁ fused with the tandem-affinity construct. CBD, calmodulin-binding domain; Chi-BD, chitin-binding domain. (B) Purification and IB analysis of the S1P₁ tandem-affinity construct. (C) Coomassie blue staining of purified S1P₁ from HEK293 cells after treatment with vehicle or FTY720P (100 nM for 30 minutes). (D) Schematic diagram of seventh transmembrane domain (TM) and C-terminal tail of S1P_1. Shown are the S-palmitoylation sites on cysteine residues (C) as well as phosphorylated serine and ubiquitinylated lysine residues identified by LC/MS/MS. Spectral counts of modified peptides are also shown.