We study how membrane bound organelles gain their unique shapes and execute their distinct functions in animal cells. We focus on the endoplasmic reticulum - the largest organelle in cells that is made up of distinct structural and functional domains, the most prominent of which is the nuclear envelope. A major goal of the lab is to understand how the domain organization of the ER is established and maintained in dividing cells, with a special emphasis on the nuclear envelope . The nuclear envelope surrounds and protects the genome and so an understanding of how the nuclear envelope is formed and maintained is important to our understanding of how the integrity of the genome is effected in diseases such as cancer. The approaches we use include high resolution quantitative fluorescence microscopy (both in mammalian cells in culture and C. elegans embryos) combined with biochemistry, protein modeling, genome engineering and classical genetics.