First, the cell surface extends a membrane process, named lamellipodium. Polymerization of actin takes place and form filaments at the leading edge, which subsequently will blend into one another to form networks. We suppose that actin polymerization is at the origine of the force propelling the cell forwards.
They are involved in a variety of cell activities, most notably:
Pseudopods can be classified into several varieties according to their appearance:
Lobopodia are bulbous, short and blunt in form, very typical of amoeba species.
Axopodia, observed mainly at radiolarians, are thin pseudopods contain complex arrays of microtubules and are enveloped by cytoplasm. Axopodia are responsible for phagocytosis, by rapidly retracting in response to physical contacts.
Reticulopodia, also known as reticulose pseudopods, are complex formations where individual pseudopods are blended together and form irregular nets.