Voeltz explains how her lab used a BioID strategy to identify some of the proteins found at membrane contact sites between the ER and endosomes; a difficult task given the transient nature of contact sites.  They were able to identify a number of proteins responsible for marking the timing and location of endosome fission and for recruiting the ER to the bud. Depleting these proteins blocked cargo sorting to the Golgi. Voeltz’ lab is now working to determine how much of this machinery is conserved in processes such as the mitochondrial