Ptc1

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.^[1]

Biological Processes

Ptc1 is involved in the following biological processes:^[1]

• 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. "Ptc1". Saccharomyces Genome Database. SGD Project. Retrieved 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. doi:10.1038/nature08946. Retrieved March 21, 2014.
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. doi:10.1128/MCB.21.1.51-60.2001. PMC 86567. PMID 11113180.