4.4: Changes to Signal Transduction Pathways

So far, we've learned about how the signal transduction pathway works, from start to finish. In topic 4.3, we explored specific examples of pathways in action. Topic 4.4 explains the factors that can boost or inhibit these pathways.

Vocab List

• Environmental factors
  • pH
  • Temperature
• Genetic factors
  • Mutations
• Inhibitors
• Activators

Written Explanation

Signal Transduction Recap:

Influences on Signal Transduction:

Since signal transduction pathways rely on enzymes, all the factors that affect enzyme function can also affect those pathways. For example, there are environmental factors that may inhibit or boost pathways. As discussed in topic 3.3, environments with a pH outside of an enzyme's normal range can cause it to denature, which would break down any pathway the enzyme was a part of. Similarly, environments with a temperature outside of an enzyme's optimal range can cause denaturation. However, environments with just slightly warmer temperatures can actually boost enzyme function, and thus signal transduction, by increasing the movement of atoms/molecules.

Genetic factors can also cause a signal transduction pathway to break down. Mutations in an organism's DNA can result in dysfunctional enzymes by modifying their amino acid composition.

Furthermore, organisms and their cells are also capable of regulating signal transduction pathways through the use of inhibitors and activators (see topic 3.3). Inhibitors that bind to either the active site (competitive) or allosteric site (noncompetitive) of an enzyme can slow down signal transduction pathways. Activators (like cofactors) can make it easier for enzymes to activate, boosting their pathways.