Peptides with phosphorylation sites found in human DDHD1

FLAG-DDHD1-expressing HEK293 or PANC1 cells were treated with okadaic acid, and FLAG-DDHD1 was purified by SDS-PAGE. After the in-gel digestion of purified FLAG-DDHD1 with trypsin or Asp-N, the resultant phosphopeptides were further purified by immobilized metal affinity chromatography (IMAC) or titanium dioxide (TiO2), zirconium dioxide (ZrO2), or TiO2/ZrO2 affinity chromatography. Peptides were analyzed by MALDI-TOF MS/MS. The Mascot analysis using the database of the human Swiss-Prot or FLAG-tagged human DDHD1 sequence revealed more than 10 phosphopeptides of DDHD1 with significant scores.