As a structural biology lab, we are interested in understanding the mechanism of molecular machines and their roles in human diseases. Currently we focus on two systems, p97 / ubiquitination system, and vault. p97 is a central hub in cellular protein homeostasis. It is involved in several neurodegenerative diseases, and is also a cancer drug target. We want to gain insights into the molecular architectures of p97 in complex with various cofactor proteins and poly-ubiquitinated substrates. We are investigating the specificity of p97 towards ubiquitin chains with various topologies. Our findings will elucidate the molecular mechanism of human p97. Vault is the largest ribonuclear protein in many eukaryotes including human. It is a membraneless organelle. Despite the fact that vault has been studied for thirty years, its function remains elusive. Overexpression of major vault protein (MVP) correlates with drug resistance in cancer cells. However, the mechanism is completely unknown at the molecular level. We are investigating the structures of vault components and using proteomic and imaging techniques to address the molecular function of vault. There are two major techniques used in the lab: X-ray crystallography and cryo-electron microscopy.