Protein Machines – Part 4

Last month I likened the tiny organelles in living cells to specialized buildings in a walled town. But how does the cell transport the goods from one facility to another? One such microscopic delivery agent is the motor protein kinesin (see animation to the right). Running on fuel known as ATP, this “FedEx agent” of the cellular world travels down a microtubule highway hand-over-hand like an orangutan moving down a jungle branch.

The longest cells in the body are the nerve cells. Transporters starting in your thigh will take about 4 days to travel down a neuron that terminates at your big toe. Without such delivery mechanisms, the cell would quickly die. But without the cellular information libraries and production facilities, there would be no way to make a highly sophisticated protein machine like kinesin. So if cells evolved, which came first: the delivery trucks that transport all the raw materials to the production plant so it can run? or the plant itself that produces all the delivery trucks?

Posted on January 1, 2018 by dwoetzel.