In contrast to these mutant Rab proteins, which promote cancer by forming trimeric complexes with SmgGDS and an oncogenic small GTPase (Nissim et al., 2019; Liao et al., 2020), the GTPase DiRas1 (also known as Rig) seems to inhibit cancer by blocking the binding of small GTPases to SmgGDS. Here, RAP1GDS1 is linked to cancer.