Additionally, the Rab INteractor 3 protein (RIN3)—a Guanine nucleotide Exchange Factor (GEF) identified as an additional risk factor underlying the genetic complexity of AD [65,96,97,98]—is reported to recruit CD2AP and BIN1 in a tripartite complex to Rab-5 GTPase-positive early endosomes [96,97,98,99] thus promoting the BACE1-dependent processing of APP in this subcellular compartment [91]. Here, RIN3 is linked to Alzheimer disease.