"Shaping and Sorting Membranes: Mechanisms of Epithelial Polarization"

This event is sponsored by FAMU-FSU Engineering Department of Chemical & Biomedical Engineering.

Abstract: Epithelial polarization is fundamental to multicellular life, underpinning processes such as morphogenesis, tissue homeostasis, and wound healing. This phenomenon depends on the compartmentalization of the plasma membrane into distinct apical and basolateral domains and the coordinated formation of a dense glycocalyx. Beyond the traditional barrier function ascribed to the apical glycocalyx, I will show the role of mucin biopolymers in generating the highly curved membrane shapes that are characteristic of polarized epithelia. We find that mucins and other large polysaccharides exert forces that influence the formation of spherical and finger-like projections, as well as more complex structures such as undulating and pearled membranes. These results suggest a fundamental role for the glycocalyx in establishing the membrane shapes that facilitate communication between cells and with the extracellular matrix. My complementary lipidomic analysis reveals that the apical membrane domains is enriched in saturated lipids, glycolipids, and cholesterol, which can self-assemble into membrane domains (i.e., lipid rafts). This raft-lipid-rich environment corresponds to higher lipid packing and recruitment of raft-preferring proteins, implicating membrane rafts in apical trafficking. Together, these findings reveal a dynamic interplay between the lipid composition and glycocalyx of the apical plasma membrane and their combined role in epithelial polarization. However, key questions remain about how these processes are coordinated, underscoring a major knowledge gap in the mechanisms underlying epithelial organization and their roles in health and disease.

Dr. Carolyn Shurer

Postdoctoral Fellow

Molecular Physiology and Biological Physics, University of Virginia

Speaker Bio: Dr. Carolyn Shurer is an engineer and biophysicist with expertise in glycobiology, lipid membrane biophysics, and protein engineering. She holds a Ph.D. in Chemical and Biomolecular Engineering from Cornell University, where her research focused on the biophysical role of the cellular glycocalyx. Currently, she is a postdoctoral fellow in Molecular Physiology and Biological Physics at the University of Virginia, exploring cell membrane organization and protein-lipid interactions. Her current research interests include the polarization of epithelial cell membranes and the dynamic interactions between proteins and lipids in living cells. Dr. Shurer’s work integrates advanced microscopy, lipidomics, and synthetic biology, resulting in numerous publications in leading journals. She is a recipient of prestigious awards, including the NIH Postdoctoral Fellowship. Dr. Shurer is also an experienced mentor and educator, actively contributing to academic training and outreach initiatives.