Seminars and Colloquia
Biology
Patterning Rho - GTPase signaling at the epithelial cadherin - junctions : a tale of feedback loops.
Tue, Jan 05, 2016,
03:00 PM to 04:00 PM
at Seminar Room 34, 2nd Floor, Main Building
Dr. Rashmi Priya
The University of Queensland,
Queensland, Australia
Epithelia are mechanically coherent tissues protecting the exteriors and interiors
of our body. Epithelial cohesion requires them to be connected via specialized
cadherin
-
based intercellular junctions. These cadherin based junctions act like
velcro,
stitch
ing cells together thus maintaining physiological integrity. However,
during development, these junctions behave like
fluid
and undergo extensive
rearrangement. This mechanical robustness and fluidity is conferred to them by a
class of molecular switches
called Rho GTPases. Rho GTPase signaling plays a
central role in the assembly and maintenance of these junctions, disruption of
which leads to
developmental
defects and pathological conditions like tumor.
Therefore, cells must harbor mechanisms to ensure
a sustained Rho signaling.
Using quantitative optical microscopy and mathematical modeling, we have now
uncovered a novel signaling apparatus which maintains an active Rho zone at
the epithelial cadherin junctions. The key here is a feedback loop mediated
by
downstream Rho
-
effector myosin II. Mathematical simulations revealed that this
feedback network has the capacity to confer bistability on signaling outcomes at
the level of populations of Rho molecules. This is predicted to promote
robustness of the Rho
zone. I will be discussing these recent findings in detail
here, which we believe carry wide implications for diverse cellular processes
relying on
Rho signaling
like cell
-
division, wound
-
healing and cell
-
migration.
