Sarah Clark, PhD
Assistant Professor, Department of Biochemistry & Biophysics
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Oregon State University
IMB Seminar Series
Jan 13, 2026
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12:00 pm
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Knight Campus Beetham Family Seminar Room
Abstract: Cells and cellular organelles are surrounded by membranes that are constantly undergoing lipid modification due to processes like cell growth, organelle biogenesis, exocytosis, and phagocytosis. Bridge-like lipid transport proteins (BLTPs) have emerged as key players in all of these processes due to their role in lipid transport. BLTPs localize to membrane contact sites, where they fold into hydrophobic tunnels that are proposed to function like “lipid superhighways” that mediate the bulk transfer of lipids from donor to acceptor membranes. Despite the fundamental importance of BLTPs for cellular function, the mechanism of lipid transfer remains enigmatic. Here, we present the subunit composition and cryo-electron microscopy structure of the native LPD-3 BLTP complex isolated from transgenic C. elegans. Our results suggest a model for how the LPD-3 complex mediates bulk lipid transport and provide a foundation for mechanistic studies of BLTPs.
Bio: Sarah Clark is an Assistant Professor in the Department of Biochemistry and Biophysics at Oregon State University. Research in the Clark lab is focused on gaining mechanistic insight into two important areas of cellular biology: sensory transduction and lipid transport. Sarah earned her B.S. in Biochemistry from the University of California, Davis, where she conducted organic chemistry research. She received her Ph.D. from Oregon State University in Molecular and Cellular Biology under the supervision of Elisar Barbar, where she studied the dynamics and function of intrinsically disordered proteins. Sarah completed her post-doctoral training in Eric Gouaux’s lab at Oregon Health and Science University, where she studied the molecular mechanisms that underlie the sensations of hearing and balance in vertebrates. During her postdoc, Sarah solved the cryo-electron microscopy structures of the protein complexes that are necessary for hearing and developed methods to study native membrane protein complexes. The Clark lab applies these methods to explore how organisms sense touch and how cells shuttle lipids from one organelle to another. The lab uses cryo-electron microscopy to visualize the architecture of the protein complexes at the heart of these cellular processes and complements structural studies with other biophysical, biochemical, and functional techniques.
Alexander Cartagena-Rivera, PhD
Investigator (Tenure-Track)
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National Institute of Biomedical Imaging and Bioengineering
IMB Seminar Series
Jan 27, 2026
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4:00 pm
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Willamette 110
The cellular glycocalyx plays a crucial role in making pancreatic cancer one of the deadliest malignancies globally. It complicates early detection and reduces the effectiveness of conventional therapies. In pancreatic cancer, the components of the glycocalyx are often upregulated or abnormally glycosylated, promoting tumor progression through immune evasion, enhanced metastasis, and drug resistance. While these biochemical effects are known, the biophysical impact of the glycocalyx on cancer cells is less understood. In our study, we explored the structural and biomechanical effects of modifying the glycocalyx architecture in pancreatic cancer cells using various chemical compounds. We employed a recently developed Atomic Force Microscopy nanomechanical mapping method to visualize cellular mechanical heterogeneities in a high spatiotemporal context. Our new approach allows for the viscoelastic inversion of high-resolution spatiotemporal data at rates which are orders of magnitude faster (more than 37,386-fold) than optimizing a traditional rheological model for each pixel. Then, we investigated the architectural and biophysical effects of glycocalyx architectural modulation in pancreatic cancer cells. Perturbations of hyaluronic acid (HA), sialic acid (SA), mucins, and N-glycans through enzymatic treatments led to significant architectural remodeling of the cell surface. Interestingly, removal of SA and mucins resulted in a softer and more fluid cell surface, while removal of HA softened and increased viscosity. In addition, preliminary cytokine expression results suggested that SA removal leads to a pronounced pro-inflammatory response (IL-2, IL-8, INF-γ among others) of human cytotoxic CD8+ T Lymphocytes, greater than removing other glycocalyx components. Lastly, a glycomics study also revealed unique changes in the structure of N- and O-glycans, with significantly more heterogeneity in the structure of N-glycans on pancreatic cancer cells, and O-glycans showing a particularly higher degree of SA deposition. Our findings suggest that the glycocalyx of human pancreatic ductal adenocarcinoma cells fundamentally regulate extracellular surface architecture, mechanical properties, composition, and function, thereby promoting tumor progression and metastasis by acting as a physical barrier to antitumor responses.
Kim McKim, PhD
Professor
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Rutgers University
IMB Seminar Series
Feb 10, 2026
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4:00 pm
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Willamette 110
Meiosis is characterized by the first, or reductional, division. We use Drosophila melanogaster females as a model to understand the mechanisms that promote accurate chromosome segregation on the acentrosomal spindle of oocytes. Furthermore, we are interested in understanding the features of the oocyte spindle that make it susceptible to chromosome segregation errors. An important part of this process is how the kinetochores on the chromosomes interact with the microtubules of the spindle. The kinetochore interacts with the microtubules in two ways. First, lateral attachments, where the kinetochores move along the sides of microtubules. Second, end-on attachments, where the kinetochores make a stable attachment to the ends of microtubules, maintain connections to a pole and segregate the homologs. The lateral interactions occur between the kinetochores and central spindle, which is composed of overlapping antiparallel microtubules and may be particularly important for acentrosomal oocytes. We hypothesize that the transition between lateral and end-on attachments is regulated to avoid errors in chromosome segregation.
Seminar details
This academic year, we will host a series of virtual and in-person seminars with live, remote access via Zoom. IMB seminars are open to the University of Oregon community, and in-person attendance is welcome. In-person seminars will be held in the Knight Campus Beetham Family Seminar Room at 12:00 p.m.
To accommodate remote speakers and time differences, some seminars may be offered at another agreed-upon time. For students taking BI 407/507 Neuroscience Seminar, please contact the course instructor to access recordings as needed.
Details for upcoming seminars will be shared here on the IMB website as well as through our IMB mailing lists. Links for remote access via Zoom will be available only through IMB seminar mailing list, and those not on the list can request access by contacting Meg Juenemann with their uoregon.edu email address.