Date: 15 June 2026 (Monday)
Time: 10:00 am – 11:00 am
Venue: Seminar Room 1, G/F, Laboratory Block, 21 Sassoon Road 
Host: Professor Tao Ni

Xia Jia is a Ph.D. candidate at Tsinghua University (2020–2026) advised by Prof. Hong-Wei Wang, after receiving her B.S. from Shandong University in 2020. Her PhD research combines cell biology, biochemistry, and cryo-electron tomography to understand how cells shape their membranes for long-range communication, focusing on pericellular protrusions. She plans to further learn multi-scale in situ structural approaches to address key biological questions.

Membrane protrusions—including filopodia, tunneling nanotubes, cytonemes, dendrites, axons, and migrasome-bearing retraction fibers—mediate long-range intercellular communication. However, the molecular mechanisms that underlie membrane tubulation and operate independently of the cytoskeleton remain poorly understood. Here, we identify TSPAN7 as a curvature-sensitive transmembrane protein that concentrates and polymerizes into spiral assemblies on membrane tubules. Using in situ cryo-electron microscopy and tomography, live-cell imaging, and in vitro reconstitution, we determine that TSPAN7 self-assembles into spiral membrane tubes, which act as a “molecular spring” to enhance membrane toughness and mechanical resilience. This work reveals a previously unrecognized, cytoskeleton-independent mechanism for stabilizing tubular protrusions, allowing them to withstand fluid shear stress and support stable intercellular signaling.

All are welcome.