Orienting the Mitotic Spindle: An optogenetic approach
Oriented cell divisions (OCDs) are essential to control tissue development and
homeostasis. They participate to fate determination of daughter cells, stem cell
proliferation and tissue growth. Defects of OCD are thus involved in
lopmental diseases. Although the core mechanisms orienting the mitotic
spindle downstream polarity cues are partly understood, little is known about the fine
spatiotemporal orchestration of this process. How are conflicting polarity signals
oes the timing of these signals determine their integration?
the modulators involved?
we raise the question of the signal processing
from cortical polarity cues down to the force generation and orientation of the mitotic
Using a novel approach combining micro
patterning and optogenetics, I
the sensitivity of OCD to polarity cues (components of the Par and LGN
complexes) and its robustness to conflicting signals (interfering gradients, polarity vs
What is the minimum level of polarity signal required to precisely orient cell
division? What signal is amplified or filtered to obtain a sensitive but robust output?
nswer these questions, I
controlled method to recruit
olarity cues at the cell cortex of dividing cells
, and measure the sensitivity
of mitotic spindle orientation to varying amounts of
precision in the polarity
I will infer from these results how the signal is processed from polar
cues to spindle orientation.
Here I present the tools
that I have developed
in order to study oriented cell division at the systems level.