  Self-propulsion and navigation due to the sensing of environmental conditions
- such as durotaxis and chemotaxis - are remarkable properties of biological
cells that cannot be reproduced by single-component self-propelled particles.
We introduce and study "flexocytes", deformable vesicles with enclosed attached
self-propelled pushing and pulling filaments that align due to steric and
membrane-mediated interactions. Using computer simulations in two dimensions,
we show that the membrane deforms under the propulsion forces and forms shapes
mimicking motile biological cells, such as keratocytes and neutrophils. When
interacting with walls or with interfaces between different substrates, the
internal structure of a flexocyte adapts, resulting in a preferred angle of
reflection or deflection, respectively. We predict a correlation between
motility patterns, shapes, characteristics of the internal forces, and the
response to micropatterned substrates and external stimuli. We propose that
engineered flexocytes with desired mechanosensitive capabilities enable the
construction of soft-matter robots.
