10.6082/UCHICAGO.1763
Vavra, Kevin Christopher
Defining Myosin-10 Navigation Rules
The University of Chicago
2016
Biochemistry
Biophysics
2019-05-08T23:20:53.0+02:00
en
Dissertation
Myosin-10 an unconventional myosin motor that localizes to tips of filopodia, long finger-
like projections from cells, to help relocate its cargo proteins to the tips and bodies of
filopodia. While it is known that myosin-10 moves along filopodial actin, how myosin-10
specifically selects for filopodial actin tracks is currently unknown. Three research groups
attempted to determine myosin-10’s track selection ability using single molecule techniques to
measure myosin-10 actin bundle selection behavior. Due to the low dimerization affinity for
myosin-10 without a high local motor concentration encouraged by cargo binding, additional
nucleation domains were needed to be attached to shortened constructs with the regulatory
cargo-binding domains removed. These studies disagreed about myosin-10 track sensitivity
because one construct demonstrated clear bundle selection not seen the other two constructs.
After these studies were performed, the native myosin-10 coiled-coil structure was solved
and showed that all three research groups had inadvertently fused an antiparallel coiled-
coil to a parallel coiled-coil. We studied the coiled-coils of the three previously designed
constructs to determine the source of different behaviors between constructs and link myosin-
10 bundle selection back to full-length wild-type myosin-10. The bundle selective construct,
which attempted to create a continuous coiled-coil, forms an antiparallel oriented coiled-coil.
Additionally this project tests the flexibility of a single-alpha helix domain connecting the
motor domain that binds actin to the coiled-coil to demonstrate how rigidity and orientation
of the coiled-coil in myosin-10 leads to actin track selection.