I. Membrane dynamics & trafficking
Membrane trafficking shuttles cargoes among intracellular compartments (a.k.a. organelles) using vesicles. This is fundamental process for the proper function of the cell, as proteins and lipids must be properly localized to perform their function. Our lab focuses on understanding how the intracellular trafficking is regulated under various physiological and pathological conditions. We recently found that polarized secretion is coordinately regulated by Rho GTPase, which is requried for rapid growth of cancer cell. Considering a growing list of diseases that are caused or exacerbated by alterations in membrane trafficking, we believe our trials to understand membrane dynamics and trafficking achieve to answer key questions about where and how diseases initiate.
II. Glycosylation in bio-medicine and bio-industry
Glycosylation is a major post-translational modification which involves protein stability and functionality in eukaryotic cells. In early studies, we found changes of glycosylation in various solid tumors including colorectal cancer and gastric cancer. Our lab keeps brodening our interest to understand how glycosylation contributes to other types of cancers such as bile duct cancer (cholandiocarcinoma) and ovarian cancer. This includes the studies using liquid biopsies for diagnosis and treatment by purifying extracellular vesicles with cancer specific glycosylation.
Glycosylation is important not only in biomedicine, but also in the bio-industry, as proper glycosylation is responsible for in vivo stability of the recombinant therapeutic proteins (e.g., antibody, and biologics). To obtain the desired glycosylation, we pursue to establish a genetically modified CHO cell line which can be used for biologic drug production. In particularly, our knowledge and experience allows us to improve the yield and quality by modifying the secretory and glycosylation pathway.
III. Organelle stress response
Eukaryotic cell regulates many cellular events in responds to environmental stresses. Over past decades, how the ER maintains protein and organelle homeostasis has been extensively studied. However, very little is known about how the quality and quantity of proteins are maintained until delivered to their final destination. Our ultimate goal is to understand how the Golgi complex controls the protein quality and quantity in the secretory pathway. Our recent approaches uncovered that the KDEL receptor, previously known as a cargo receptor, acts as a stress sensor by examining how much proteins enter the Golgi complex. Multiple approaches (e.g., x-ray structural analysis, EM tomography, glycomics and spatiotemporal interactome analysis) provide a better understanding of how the Golgi complex responds to the stress and acts for protein homeostasis.