We study the molecular mechanisms that underlie intracellular transport and seek to understand how proteins catalyze distinct sub-reactions in the early secretory pathway. Our current focus is on the mechanisms of protein transport between the ER and Golgi complex. We study this process in yeast and animal cell models using biochemistry, molecular genetics and microscopy. Transport of newly synthesized proteins from the ER to Golgi compartments is essential for cell growth and function with approximately one-third of a cell's translated proteins entering the secretory pathway. Several genetic diseases in humans are connected to deficiencies in ER quality control and trafficking, therefore understanding these mechanisms are important for the prevention and treatment of numerous health related issues and are specifically relevant to understanding cholesterol regulation, Alzheimer's disease and cystic fibrosis.