Guanine nucleotide exchange factor (GEF) regulating clathrin-mediated endocytosis through RAB35 activation. Promotes the exchange of GDP to GTP, converting inactive GDP-bound RAB35 into its active GTP-bound form. Regulates clathrin-mediated endocytosis of synaptic vesicles and mediates exit from early endosomes (PubMed:17182770, PubMed:20159556). Binds phosphatidylinositol-phosphates (PtdInsPs), with some preference for PtdIns(3)P (PubMed:20159556). The guanine nucleotide exchange factor (GEF) activity is autoinhibited. Autoinhibition may be the result of intramolecular interaction between the DENN domain and the C-terminus, which is disrupted upon phosphorylation. Activation is regulated by Akt activation. Interacts with RAB35 (PubMed:20159556). Interacts with clathrin and with the adapter protein complex 2, AP-2 (By similarity). Interacts with ITSN1 AND SH3GL2 (PubMed:17182770). Interacts (when phosphorylated) with YWHAE (By similarity). Associates to membranes via lipid-binding activity. Phosphorylated on serine and/or threonine in an Akt-dependent manner. Phosphorylation probably regulates the guanine nucleotide exchange factor (GEF) activity, possibly by disrupting an intramolecular interaction between the DENN domain and the C-terminus of the protein, thereby relieving the autoinhibition.