The wonders of the molecular world animated Janet Iwasa
I live in Utah,
a place known for having
some of the most awe-inspiring
natural landscapes on this planet.
It’s easy to be overwhelmed
by these amazing views,
and to be really fascinated by these
sometimes alien-looking formations.
As a scientist, I love
observing the natural world.
But as a cell biologist,
I’m much more interested
in understanding the natural world
at a much, much smaller scale.
I’m a molecular animator,
and I work with other researchers
to create visualizations
of molecules that are so small,
they’re essentially invisible.
These molecules are smaller
than the wavelength of light,
which means that we can
never see them directly,
even with the best light microscopes.
So how do I create
visualizations of things
that are so small we can’t see them?
Scientists, like my collaborators,
can spend their entire
professional careers
working to understand
one molecular process.
To do this, they carry out
a series of experiments
that each can tell us
a small piece of the puzzle.
One kind of experiment
can tell us about the protein shape,
while another can tell us
about what other proteins
it might interact with,
and another can tell us
about where it can be found in a cell.
And all of these bits of information
can be used to come up with a hypothesis,
a story, essentially,
of how a molecule might work.
My job is to take these ideas
and turn them into an animation.
This can be tricky,
because it turns out that molecules
can do some pretty crazy things.
But these animations
can be incredibly useful for researchers
to communicate their ideas
of how these molecules work.
They can also allow us
to see the molecular world
through their eyes.
I’d like to show you some animations,
a brief tour of what I consider to be
some of the natural wonders
of the molecular world.
First off, this is an immune cell.
These kinds of cells need to go
crawling around in our bodies
in order to find invaders
like pathogenic bacteria.
This movement is powered
by one of my favorite proteins
called actin,
which is part of what’s known
as the cytoskeleton.
Unlike our skeletons,
actin filaments are constantly
being built and taken apart.
The actin cytoskeleton plays
incredibly important roles in our cells.
They allow them to change shape,
to move around, to adhere to surfaces
and also to gobble up bacteria.
Actin is also involved
in a different kind of movement.
In our muscle cells, actin structures
form these regular filaments
that look kind of like fabric.
When our muscles contract,
these filaments are pulled together
and they go back
to their original position
when our muscles relax.
Other parts of the cytoskeleton,
in this case microtubules,
are responsible for long-range
transportation.
They can be thought of
as basically cellular highways
that are used to move things
from one side of the cell to the other.
Unlike our roads,
microtubules grow and shrink,
appearing when they’re needed
and disappearing when their job is done.
The molecular version of semitrucks
are proteins aptly named motor proteins,
that can walk along microtubules,
dragging sometimes huge cargoes,
like organelles, behind them.
This particular motor protein
is known as dynein,
and its known to be able
to work together in groups
that almost look, at least to me,
like a chariot of horses.
As you see, the cell is this incredibly
changing, dynamic place,
where things are constantly
being built and disassembled.
But some of these structures
are harder to take apart
than others, though.
And special forces need to be brought in
in order to make sure that structures
are taken apart in a timely manner.
That job is done in part
by proteins like these.
These donut-shaped proteins,
of which there are many types in the cell,
all seem to act to rip apart structures
by basically pulling individual proteins
through a central hole.
When these kinds of proteins
don’t work properly,
the types of proteins
that are supposed to get taken apart
can sometimes stick together and aggregate
and that can give rise
to terrible diseases, such as Alzheimer’s.
And now let’s take a look at the nucleus,
which houses our genome
in the form of DNA.
In all of our cells,
our DNA is cared for and maintained
by a diverse set of proteins.
DNA is wound around proteins
called histones,
which enable cells to pack
large amounts of DNA into our nucleus.
These machines
are called chromatin remodelers,
and the way they work
is that they basically scoot the DNA
around these histones
and they allow new pieces of DNA
to become exposed.
This DNA can then be recognized
by other machinery.
In this case, this large molecular machine
is looking for a segment of DNA
that tells it it’s
at the beginning of a gene.
Once it finds a segment,
it basically undergoes
a series of shape changes
which enables it to bring in
other machinery
that in turn allows a gene
to get turned on or transcribed.
This has to be a very
tightly regulated process,
because turning on the wrong gene
at the wrong time
can have disastrous consequences.
Scientists are now able
to use protein machines
to edit genomes.
I’m sure all of you have heard of CRISPR.
CRISPR takes advantage
of a protein known as Cas9,
which can be engineered
to recognize and cut
a very specific sequence of DNA.
In this example,
two Cas9 proteins are being used
to excise a problematic piece of DNA.
For example, a part of a gene
that may give rise to a disease.
Cellular machinery is then used
to basically glue two ends
of the DNA back together.
As a molecular animator,
one of my biggest challenges
is visualizing uncertainty.
All of the animations I’ve shown to you
represent hypotheses,
how my collaborators think
a process works,
based on the best information
that they have.
But for a lot of molecular processes,
we’re still really at the early stages
of understanding things,
and there’s a lot to learn.
The truth is
that these invisible molecular worlds
are vast and largely unexplored.
To me, these molecular landscapes
are just as exciting to explore
as a natural world
that’s visible all around us.
Thank you.
(Applause)