Consider a signaling pathway that proceeds through three protein kinases that are sequentially activated by phosphorylation. In

Question:

Consider a signaling pathway that proceeds through three protein kinases that are sequentially activated by phosphorylation. In one case, the kinases are held in a signaling complex by a scaffolding protein; in the other, the kinases are freely diffusible (Figure Q15–1). Discuss the properties of these two types of organization in terms of signal amplification, speed, and potential for cross-talk between signaling pathways.

Figure Q15-1

CYTOSOL 3 3