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BIOPHYSICAL SOCIETY NEWSLETTER
8
SEPTEMBER
2017
Biophysical Journal
Know the Editors
Margaret Gardel
University of Chicago
Editor for the Molecular
Machines, Motors, and
Nanoscale Biophysics Section
Q.
What has been your biggest “aha”
moment in science?
There are two moments that come to mind.
The first happened in graduate school. I had been
studying the mechanical properties of cross-linked
actin networks formed in vitro. I was visiting
John
Crocker’s
lab at the University of Pennsylvania,
where they were measuring the mechanical prop-
erties of adherent cells. We were puzzling over
why the stiffness I measured was 1000-fold softer
than that measured in the adherent cell cortex,
although protein concentrations were comparable.
Then, we wondered if the non-linear elasticity of
the in vitro networks, a dramatic
stiffening that occurs when an external force is ap-
plied, might explain this difference. The actin cor-
tex of cells contains myosin II, which we thought
could “pre-stress” the networks. Once we realized
that applied force was the relevant parameter, we
were quickly able to match cell rheology measure-
ments from several groups to the in vitro data I
had collected. Within a few days, data I had col-
lected over the course of several years became the
basis of a manuscript that was published in PNAS
that identified pre-stress as an important control
parameter of cell rheology. The second “aha”
moment occurred very recently. My lab has been
working hard to understand how contractile forces
arise in mixtures of actin filaments and myosin II
motors. Other labs have been looking at mixtures
of microtubules and microtubule-based motors
and have described extensility in these systems. I
have been puzzled the past few years over how
different motor-filament arrays exhibit contraction
or extension. Very recently, a postdoc and grad
student in my lab have discovered that actomyosin
mixtures can also exhibit extensility. The moment
they showed me data resolved years of confu-
sion! We, and others, are now discovering how to
control the emergent properties of motor-filament
systems to be either contractile or extensile.
Q.
How do you stay on top of all the
latest developments in your field?
This is very hard and I can’t say I do a perfect
job of it. I agree to be the editor of relevant
manuscripts submitted to
Biophysical Journal
and
Molecular Biology of the Cell
, two of my favorite
journals. I agree to review papers. I also agree to
review grants and am a standing member of a Na-
tional Institutes of Health study section. I send my
students and postdocs to meetings and ask them
to report back to the lab on what they learned. My
lab has a bi-weekly journal club: we are currently
using the Pollard model in which every person has
10 minutes to present a paper of their choice.
Margaret Gardel