Ptc1 Explained

Ptc1 is a type Two C phosphatase^[1] involved in the mating decision of yeast. Ptc1 competes with Fus3 for control of the 4 phosphorylation sites on the scaffold protein Ste5. Presence of the mating pheromone α-factor causes Ptc1 to be recruited to Ste5. This recruitment takes place via a 4 amino acid motif in the Ste5 phosphosites.^[2]

Ptc1 is also involved in regulating the osmotic stress of yeast, especially via inactivation of Hog1, a member of the MAPK pathway. This inactivation occurred as a result of dephosphorylation of the phosphotheronine but not the phosphotyrosine residue in the phosphorylation lip of Hog1.^[3]

It can be localized to the cytoplasm and nucleus.

Biological Processes

Ptc1 is involved in the following biological processes:

• Inactivation of MAPK activity in osmosensory signalling pathways
• Mitochondrial inheritance
• Pheromone-dependent signal transduction in conjugation with cellular fusion
• Protein dephosphorylation
• tRNA splicing via. Endonucleolytic cleavage and ligation

References

1. Web site: Ptc1 . . Saccharomyces Genome Database . SGD Project . 21 March 2014.
2. Malleshaiah . Mohan . 6 May 2010 . The scaffold protein Ste5 directly controls a switch-like mating decision in yeast . Nature . 465 . 7294 . 101–105 . 10.1038/nature08946. 20400943. 2010Natur.465..101M . 4419254 .
3. Warmka . Janel . Jan 2001 . Ptc1, a Type 2C Ser/Thr Phosphatase, Inactivates the HOG Pathway by Dephosphorylating the Mitogen-Activated Protein Kinase Hog1 . Molecular and Cellular Biology . 21 . 1 . 51–60 . 10.1128/MCB.21.1.51-60.2001. 86567 . 11113180.