NSF/Bio-DFG: Supramolecular organization of the antigen processing machinery in the ER membrane

About This Grant

The endoplasmic reticulum (ER) is found in all eukaryotic cells and functions in many essential processes. The project will provide a better understanding of how various ER structures, such as tubules and sheets, determine where proteins of the ER accumulate and interact. These studies will ultimately reveal how the ER can serve multiple roles in cells and will assist in generating a more complete picture of the entire ER system. The project will focus on the role of the ER in immune recognition (i.e., how cells recognize what is “self” and what is “non-self”). The Broader Impact of the work includes its intrinsic merit as the ER as a ubiquitous organelle. It also could provide understanding of how some viruses escape notice by the immune system. Other activities include the training of graduate students and postdoctoral researchers in interdisciplinary research that bridges physics, biophysics, cell biology and biochemistry, preparing them for a career in research at universities or in industry. The project will also provide local high school students an opportunity to participate in hands-on learning experiences and benefit other students with optics demonstrations. These outreach activities are designed to inspire students to pursue STEM careers. Through these outreach and training initiatives, this project will contribute to the development of a well-equipped STEM workforce in the United States, fostering the next generation of scientists and engineers. This research examines the nanoscale organization of the peptide loading complex (PLC) within the ER, focusing on its structural relationship with the transporter associated with antigen processing (TAP1/2). The complex plays a critical role in assembling major histocompatibility complex class I molecules, which are essential for immune recognition. The project aims to determine how ER morphology influences the function of the complex, thereby providing insight into the broader role of ER architecture in cellular processes. By employing advanced super-resolution microscopy techniques such as DNA-PAINT and 4Pi-SMS, the study will map the spatial distribution of PLC clusters and quantify their size and stoichiometry. Additionally, the research will explore how modulating the PLC’s supramolecular organization affects its function, shedding light on the structural determinants of its activity. This investigation will combine expertise in biochemistry, structural biology, and high-resolution imaging, drawing on the collaborative strengths of the Tampé lab (Frankfurt) and the Bewersdorf lab (Yale). By systematically integrating these methodologies, the project aims to build a comprehensive model of how ER nanomorphology supports cellular processes essential to immune function. The insights gained from this study will not only deepen our understanding of antigen presentation but also contribute to the broader field of ER research by elucidating how macromolecular assemblies are spatially regulated within cellular compartments. This collaborative US/Germany project is supported by the US National Science Foundation and the German Deutsche Forschung Gemeinschaft (DFG) where NSF funds the US investigator and DFG funds the German partner. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.