“…To define TrkA-dependent pathways that drive macropinocytosis, we focused on molecules that serve roles in clathrin-independent endocytosis and macropinocytosis-dependent actin remodeling. Collectively, these include PAK1, PI3 kinase, and Src (32), as well as several GTPases, including H-Ras, Cdc42, Rac1, Rab5, Arf1, Arf6, RhoA, and CtBP1/BARS (15,16,21,33,34,35). With respect to Trk signaling, TrkA has been shown to activate H-Ras, Rap-1, Rac, and Cdc42 as well as to negatively regulate RhoA, depending on the cellular context (36)(37)(38)(39)(40)(41)(42)(43)(44)(45).…”