To further confirm whether endogenous SIRT1 and PLD isozymes can form a natural complex in colorectal cancer cells (HT119 and HT29 cells) and A549 lung adenocarcinoma cells, which express both endogenous PLD1 and PLD2 (Fig. 1d), we performed coimmunoprecipitation assays. Here, GPLD1 is linked to colorectal cancer.