Indeed, we have shown that elevation of the CTD Ser2P and Ser5P (caused by the mutation in the CPL1-encoed CTD Ser5 phosphatase gene) did lead to activation of ROP GTPase in Arabidopsis plants (Supplementary Figure S2), and thus future research is necessary to determine whether reduction of DOCK4 and DOCK9 in human cancer cell culture indeed leads to lower activity of Rac1 and Cdc42, respectively. Here, DOCK4 is linked to cancer.