Th1L06 Lamellipodia (actin based movement)

When lamellipodia or filopdia touch down they attach to the extracellular matrix through the formation of focal adhesions (focal contacts) Actin filaments connect the focal adhesion to the rest of the cytoskeleton Then, myosin motor protein pull on actin filaments to drag the cell forward Myosin II filaments doesn't stay bound to actin all the time (unusual) Myosin is one class of proteins called motor proteins Myosin 'head region' interacts with actin and binds ATP Energy release from ATP hydrolysis forces the myosin tail to move, generating force ADP is released from the myosin head and replaced by ATP at which stage the head can detach from the actin filament the head binds further down the filament Non-processive motor protein e.g. myosin II detaches completely from actin filaments at the end of the cycle will travel only short distances constantly bound and un-bound depending on hydrolysis of ATP