Th1L06 Lamellipodia (actin based movement)

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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