Which of the following effects is least likely to be mediated by a scaffolding protein?

A Increase the local concentration of signaling components.

B Increase allosteric effects and cooperative binding of second messengers to their targets.

C Regulate the order in which a series of kinases can become activated following receipt of a signal.

D Decrease likelihood of crosstalk between signaling pathways that share a common kinase.

E Allow rapid negative feedback of a signaling response.

The correct answer is: B Increase allosteric effects and cooperative binding of second messengers to their targets.

Scaffold proteins are considered regulatory proteins that affect many signal pathways. Some of their functions are:

• Regulation and coordination of positive and negative feedback signals

• Localizing signal components within the cell (in different cell compartents)

• tethering signaling components (assembling signal components into complexes in order to increase signal efficiency).