Final answer:
Akt stimulates cells to grow in size by activating Tor, a serine/threonine kinase. Tor phosphorylates and activates downstream targets involved in cell growth and size regulation.
Step-by-step explanation:
Akt is a protein kinase that plays a role in cell growth and survival. When Akt is activated, it stimulates cells to grow in size by activating another protein kinase called Tor (target of rapamycin). Tor is a serine/threonine kinase that regulates cell growth and metabolism.
When Akt activates Tor, it phosphorylates and activates Tor, which in turn phosphorylates and activates downstream targets involved in cell growth and size regulation. This leads to an increase in protein synthesis, cell proliferation, and overall cell growth.
For example, Akt activation of Tor can result in the activation of ribosomal protein S6 kinase (S6K), which promotes protein synthesis and cell growth. Akt can also activate another downstream target called eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), which promotes protein synthesis and cell growth by allowing the initiation of translation.