What are microfilaments?
Cytoskeletal structures made of actin
A cell has various structures that hold things up or pull things apart or are used as little highways. Microfilaments make up some of these structures, notably the structure the cell uses to push forward for motile cells, and acting as a tread for myosin to trundle along on.
Actin combines into filaments that are constantly being added to at a plus end and removed from at a minus end. These filaments interact with things like cofilin, profilin, filimin, CAPZ and other things that help the filaments to grow, shrink and keep constant. In the case of motility, cells can create long filaments to reach out, then pull themselves along.
Mechanobiology institute, Singapore.
This should give you an idea about how the filaments extend and shrink via nucleation