Calendar Name: seminars
Scheduled for: Thursday, March 17 2011, 11:00 - 12:30
Event text: Dr John Runions
Oxford Brookes University
School of Life Sciences
Oxford
UK
Details: "Plant cell membrane protein dynamics"
ABSTRACT
Cell membrane proteins play a key role in the ability of
plants to sense and respond to their environments. We
have been utilizing live-cell imaging techniques to
study protein interactions within and across the plasma
membrane. A clue to the way in which membrane proteins
associate with each other is in the way in which they
diffuse within the plasma membrane. Using
photoactivation and photobleaching of fluorescent
proteins, we have been able to determine that different
types of proteins have differing mobility and we are now
working to determine how protein conformation and
insertion into membranes govern mobility
characteristics. I will illustrate the technique that we
have developed by describing three recent case studies.
Plants regulate plasma membrane viscosity by altering
their fatty acid composition in response to temperature
fluctuations. We have determined, however, by examining
diffusion of the membrane marker LTI6b-GFP that these
alterations maintain homeostasis of membrane viscosity.
Secondly, the plasma membrane protein formin1 is an
actin cytoskeleton regulatory protein that remains
relatively immobile and we have determined that it is
anchored through association with the cell wall. This
is the first report of a protein bridging between the
cytoskeleton and the cell wall. Finally, a new study
with colleagues at VIB, Gent has revealed that lateral
mobility of PIN proteins and ultimately their
asymmetrical distribution in polarized cells is
controlled by interactions with the extracellular
matrix.
These findings should be of general interest to
physiologists, cell biologists and developmental
biologists alike. Understanding the mechanisms of
protein associations at the cell membrane will be key to
new discoveries in these fields.
