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. 1 2 3 "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.