| Modification Notes |
In Saccharomyces cerevisiae, the Target of Rapamycin, or Tor pathway, mediates cell proliferation and growth. Two A phosphatase Associated Protein, or Tap42, is part of the Tor signalling pathway and is involved in transcriptional modulation. Tap42 is phosphorlyated by Tor and interacts with the catalytic subunits of protein phosphatase 2A (PP2A) and closely related phosphatase Sit4 via their N-terminal domains. Tap42 can also interact with Pph3 and Ppg1, two 2A-like phosphatases. Tap42 acts as an inhibitor of PP2A phosphatase, and the the complex between Tap42 and the catalytic subunit of PP2A acts via a Rho GTPase-dependent mechanism to regulate the actin cytoskeleton in S. cerevisiae. Upon treatment with rapamycin, Tap42 interacts with TIP41 , which binds to and inhibits Tap42. In mammals, the homolog of Tap42 is known as alpha4. |