Vertebrate DOCK 4 was originally identified as a CDM family member capable ofactivating the small GTPase Rap1 in GTPase pull-down assays [56].Functionally, a deletion of endogenous DOCK4 in osteosarcoma cells was shown torescue the formation of adherens junctions and could be suppressed byco-expression of dominant-negative Rap1 [56]. This evidence concerns the gene DOCK4 and osteosarcoma.