What are Kinases?

Kinases are special proteins in living cells that send signals to regulate virtually all cellular activities, including growth, survival, death, movement and responsiveness to hormones and growth factors. There are approximately 520 human kinases. Because of their crucial role in maintaining normal cell health and physiology, their activities are tightly regulated.

In living cells, kinases are regulated by control of their shape. ON shapes actively send signals within the cell, while OFF shapes maintain kinases in inactive states. Most kinases are predominantly maintained in their OFF shapes, and only are called upon to adopt ON shapes for brief cell signaling events. Internal molecular switches control the kinase shape through occupancy of kinase switch pockets.

• Activating (+) switches move a kinase into its ON shape by occupying the switch pocket:
  (+) green arrow in figure below.
• Inhibitory (-) switches move a kinase into its OFF shape by occupying the switch pocket:
  (-) green arrow in figure below.