Movement of any type in an organism depends on the cytoskeleton and motor protei

The three categories of movement are transport, pushing, and pulling movements. In the first type of movement, the cytoskeleton acts as a path or road on which the motor proteins can move. As they move up and down the cytoskeleton, they carry vesicles filled with secretory or membrane proteins to the appropriate part of the cell. This is important for carrying endocrine or neural secretions to the point of their release. The pushing type of movement relies on the growth of microtubules in the cytoskeleton. This form of movement is unique in that the use of motor proteins is not necessary. Instead, it may utilize the increase and decrease in the length of the proteins to push the cytoplasm of the cell from one place to another. It is often called amoeboid movement and is used by leukocytes and protists. The last type of movement involves pulling on cytoskeletal proteins using motor proteins. This is seen in flagellar and muscle movement.