Biological complexity: cell migration motors (Introduction)

by David Turell , Monday, December 11, 2017, 15:50 (2539 days ago) @ David Turell

Cells in the body have to migrate to heal a wound as one example of the requirement. How the cell moves is described:

https://phys.org/news/2017-12-internal-cell-migration-revealed-live-cell.html

"How do cells move in a certain direction in the body—go to a wound site and repair it, for example, or hunt down infectious bacteria and kill it?

"Two new studies from the Marine Biological Laboratory (MBL) show how cells respond to internal forces when they orient, gain traction, and migrate in a specific direction. The research, which began as a student project in the MBL Physiology Course and was developed in the MBL Whitman Center, is published in Proceedings of the National Academy of Sciences (PNAS) and this week in Nature Communications.

"Both papers focus on the activation of integrins, proteins that allow cells to attach to their external environment and respond to signals coming from other cells. Integrins are transmembrane proteins: part lies on the cell surface and part lies inside the cell. Using a microscope invented at the MBL, the authors showed that when integrins unfurl from the cell surface and bind extracellularly, they simultaneously align in the same direction as a force inside the cell (actin retrograde flow).

"'If you think of a cell as a car, the actin flow is the engine," says Clare Waterman, a Whitman Center Scientist from the National Heart, Lung and Blood Institute. "The cell can sit there, idling its engine. But when the integrins activate and bind externally, they are like the tires hitting the road, providing friction. The engine goes into gear and the car moves."

***

"There are 24 different types of integrins found on human cells. The PNAS paper studies an integrin on fibroblast cells while the Nature Communications paper analyzes an integrin on white blood cells.

"'The two integrins we worked on were about as structurally different as you can get in the integrin family," says Springer, yet both types, when activated, oriented in a direction dictated by intracellular actin flow.

"'This is really beautiful basic research," Springer says. "While we knew a lot about highly purified integrins in solution, this research gives us specific information about their activation state in living cells.'"

Comment: A wonderful depiction of how cells can migrate. The initiation of movement must be a response to a stimulus/stimuli, but that is not part of this study.