Direction of Motion
Motor proteins travel in a specific direction along a microtubule. This is because the microtubule is polar and the heads only bind to the microtubule in one orientation, while ATP binding gives each step its direction through a process known as neck linker zippering.
Most kinesins walk towards the plus end of a microtubule which, in most cells, entails transporting cargo from the centre of the cell towards the periphery. This form of transport is known as anterograde transport/orthrograde transport. Kinesin-14 family proteins, such as Drosophila melanogaster NCD, budding yeast KAR3, and Arabidopsis thaliana ATK5, walk in the opposite direction, toward microtubule minus ends.
A different type of motor protein known as dyneins, move towards the minus end of the microtubule. Thus they transport cargo from the periphery of the cell towards the centre, for example from the terminal buttons of a neuronal axon to the cell body (soma). This is known as retrograde transport.
Read more about this topic: Kinesin
Famous quotes containing the words direction of, direction and/or motion:
“Not I, not I, but the wind that blows through me!
A fine wind is blowing the new direction of Time.”
—D.H. (David Herbert)
“Each man has his own vocation. The talent is the call. There is one direction in which all space is open to him. He has faculties silently inviting him thither to endless exertion. He is like a ship in the river; he runs against obstructions on every side but one; on that side all obstruction is taken away, and he sweeps serenely over a deepening channel into an infinite sea.”
—Ralph Waldo Emerson (1803–1882)
“On board ship there are many sources of joy of which the land knows nothing. You may flirt and dance at sixty; and if you are awkward in the turn of a valse, you may put it down to the motion of the ship. You need wear no gloves, and may drink your soda-and-brandy without being ashamed of it.”
—Anthony Trollope (1815–1882)