They can also be repressed by Cdc42‐GTP, a first example of the CRIB domain effect.33 Cdc42ep5 and Cdc42ep2 can bind septins via their BH3 domain and induce septin filament bundling.23, 33 Further characterization demonstrated that Cdc42ep5 binds specifically to septin 6/7 heterodimers or septin 2/6/7 trimers, but not to septin monomers.35 Using super‐resolution microscopy, it was shown that Cdc42ep3 forms an intricate filamentous network in cancer‐associated fibroblasts that colocalized with septin filaments. This evidence concerns the gene CDC42EP5 and cancer.