We are studying how ER contact sites and branched actin regulate endosome bud formation, cargo sorting, and ER-associated fission. We have identified factors involved through turboID experiments and these factors have revealed insight into the mechanism. We are also studying whether ER contact sites regulate endosome fusion. We aim to identify machineries involved and probe how they recruit factors involved in endosome trafficking, maturation, tethering, and the timing of fusion. We are generated reporter constructs to further probe the role of ER Ca2+ release in these activities.