Featured Member

Seham Ebrahim


I am an Assistant Professor in the Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine. I was born in Karachi and grew up in Dubai I did postdoctoral work at NIH with Drs Bechara Kechar and Roberto Weigert after my PHD (Biological Sciences, Queen Mary University of London). My laboratory works on the mechanobiology of the cellular response to environmental changes. Our focus is on cytoskeletal network dynamics networks during channel mechano sensing in intestinal epithelia during inflammation, cancer, and aging.

See “www.med.virginia.edu/ebrahim-lab” for more.


In vivo, the cytoskeletal components actin and non-muscle myosin II (NMIIA) employ myriad distinct architectures, dynamics, and interactions to conduct specialized functions. These architectures cannot be fully recapitulated and studied in in vitro. Intravital microscopy imaging allowed the study of the 4D cellular physiology of the cytoskeleton in native tissues.

The study used four-dimensional spinning-disc confocal microscopy with image deconvolution to acquire macromolecular-scale detail of dynamic actomyosin networks in exocrine glands of live mice. We addressed how actin and NMIIA organize into previously undescribed polyhedral-like lattices around large membrane-bound secretory vesicles and generate the forces required to complete exocytosis. We show using photobleaching and pharmacological perturbations in vivo that actomyosin contractility and actin polymerization together push on the underlying vesicle membrane to complete exocytosis. The Figure shows a model for lattice assembly and dynamics (see1 for details).

  1. Ebrahim, S. et al. Dynamic polyhedral actomyosin lattices remodel micron-scale curved membranes during exocytosis in live mice. Nat Cell Biol 21, 933-939 (2019).