The importance of mechanics in biological design can be seen all
around us, from spider webs to the musculoskeletal system. This
relationship extends to the microscopic world and our lab investigates
how mechanics control biological functioning on small length-scales,
ranging from protein shells to multicellular assemblies.
To understand the steps that lead to viral infection, we study the
mechanical properties of virus capsids at different stages of their
life cycle. It is now well established that viruses are very robust
when they travel between host organisms but we showed how mechanical
changes of their protein shell eventually allow them to open up to
release their genetic material1
. In the case of influenza virus, we discovered that sequential uncoating steps are required to achieve maximal infectivity2
Along similar lines, we aim to understand the mechanical contribution
of clathrin protein lattices to the formation of membrane vesicles in
cells, an essential process in endocytosis and intracellular transport.
The lessons that we learn from studying the mechanical architecture of
such biological complexes can also be exploited to improve their
application in nanotechnology. For example, clathrin proteins, normally
involved in the formation of transport vesicles in cells, can be
applied to form very regular and stable lattices on almost any type of
. This surface functionalization could be a first step to fabricate more efficient sensors or biosynthetic reactors.
To measure the mechanical response, we indent or stretch our samples on
a sub-micrometer length-scale using atomic force microcopy, optical
trapping, and standing acoustic waves4
. Because we perform
our experiments in a controlled liquid environment, we can mimic events
that are triggered by temperature, chemicals, pH, or force. Finite
element analysis is employed to model the experiments in order to
extract the relevant mechanical parameters.
Most of our research projects are carried out as national or
international collaborations, in which we provide the nano-mechanical
expertise while our partners are experts on the specific biological
(1) A. Ortega-Esteban, K. Bodensiek, C. San Martín, M. Suomalainen,
U.F. Greber, P.J. de Pablo, I.A.T. Schaap (2015) Fluorescence tracking
of genome release during the mechanical unpacking of single viruses.
ACS Nano. 9, 10571-10579.
(2) S. Li, C. Sieben, K. Ludwig, C.T. Höfer, S. Chiantia, A. Herrmann,
F. Eghiaian, I.A.T. Schaap (2014) pH-controlled two-step uncoating of
influenza virus. Biophys. J. 106, 1447-1456.
(3) P.N. Dannhauser, M. Platen, H. Böning, I.A.T. Schaap (2015) Durable
protein lattices of clathrin that can be functionalized with
nano-particles and active bio-molecules. Nat. Nanotechnol. 10, 954-957.
(4) A. Lamprecht, S. Lakämper, T. Baasch, I.A.T. Schaap, J. Dual (2016)
Imaging the position-dependent 3D force on microbeads subjected to
acoustic radiation forces and streaming. Lab Chip. 16, 2682-2693.
(5) S. Nawaz, P. Sánchez, S. Schmitt, N. Snaidero, M. Mitkovski, C.
Velte, B.R. Brückner, T. Czopka, S. Jung, J.S. Rhee. A. Janshoff, W.
Witke, I.A.T. Schaap, D. Lyons, M. Simons (2015) Actin filament
turnover drives leading edge growth during myelin sheath formation in
the central nervous system. Dev. Cell. 34, 139-151
We are part of the Institute of Biological Chemistry, Biophysics and
Bioengineering (IB3) at the Heriot Watt University in Edinburgh, UK.
Dr. Iwan A.T. Schaap
tel: +44 131 451 4145
i.schaap (at) hw.ac.uk
Institute of Biological Chemistry, Biophysics and Bioengineering
School of Engineering and Physical Sciences
EH14 4AS Edinburgh, UK