BEGIN:VCALENDAR VERSION:2.0 PRODID:-//jEvents 2.0 for Joomla//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT UID:3aa8ac2ca7c446d1a64e86d9a760cc53 CATEGORIES:Seminar CREATED:20181113T151933 SUMMARY:Dr. Zheng Shi DESCRIPTION:
Wednesday November 28 , 2018
11:00AM, Room 1203
Hos ted by Professor Andrew Nieuwkoop
"Mechan ical Signaling at the Cell Membrane"
Membrane tension affects cell mi gration, vesicle fusion and recycling, the cell cycle, cell signaling, and mechanosensation. The fluid-mosaic model posits a liquid-like plasma membra ne, which can flow in response to tension gradients. It is widely assumed t hat membrane flow transmits local changes in membrane tension across the ce ll in milliseconds. This conjectured signaling mechanism has been invoked t o explain how cells coordinate changes in shape, motility, and vesicle fusi on, but the underlying propagation has never been observed.
In this t
alk, I will begin with showing how membrane tension controls membrane curva
ture and protein-membrane binding with a synthetic membrane system. Then, I
will show that in biological membranes, propagation of membrane tension oc
curs quickly in cell-attached blebs but is largely suppressed in intact cel
ls. The failure of tension to propagate in cells is explained by a fluid dy
namical model that incorporates the flow resistance from cytoskeleton-bound
transmembrane proteins. Perturbations to tension propagate diffusively, wi
th a diffusion coefficient ?0.024 ?m2/s. Local
increases in membrane
tension lead only to local activation of mechanosensitive ion channels and
to local vesicle fusion. Thus, membrane tension is not a mediator of long-r
ange intracellular signaling, but local variations in tension mediate disti
nct processes in sub-cellular domains.
< strong>Wednesday November 28, 2018
11:00AM, Room 120 3
Hosted by Professor Andrew Nieuwkoop
< p class="red-phrase">"Mechanical Signaling at the Cell Membrane"Memb rane tension affects cell migration, vesicle fusion and recycling, the cell cycle, cell signaling, and mechanosensation. The fluid-mosaic model posits a liquid-like plasma membrane, which can flow in response to tension gradi ents. It is widely assumed that membrane flow transmits local changes in me mbrane tension across the cell in milliseconds. This conjectured signaling mechanism has been invoked to explain how cells coordinate changes in shape , motility, and vesicle fusion, but the underlying propagation has never be en observed.
In this talk, I will begin with showing how membrane ten
sion controls membrane curvature and protein-membrane binding with a synthe
tic membrane system. Then, I will show that in biological membranes, propag
ation of membrane tension occurs quickly in cell-attached blebs but is larg
ely suppressed in intact cells. The failure of tension to propagate in cell
s is explained by a fluid dynamical model that incorporates the flow resist
ance from cytoskeleton-bound transmembrane proteins. Perturbations to tensi
on propagate diffusively, with a diffusion coefficient ?0.024 ?m2/s. Local
increases in membrane tension lead only to local activation of mechan
osensitive ion channels and to local vesicle fusion. Thus, membrane tension
is not a mediator of long-range intracellular signaling, but local variati
ons in tension mediate distinct processes in sub-cellular domains.