Figure 5.

Signal transduction in protease signalling. A hypothetical signal transduction pathway is shown with the first step being a proteolytic processing of its substrate leading to the activation of the latter. This triggers a chain reaction of events, leading to transfer of the signal. However, if the cellular or reaction threshold (inhibitors, autophagy, …) is not overcome, the signal is not transmitted. If a protease is inactivated/degraded during the process, the signal can be transmitted if the overall threshold is overcome. Similar is true for subsequent processing/degradation or milieu-mediated inactivation of the protease substrate(s).