Ptc1 is a type Two C

phosphatase In biochemistry, a phosphatase is an enzyme that uses water to cleave a phosphoric acid Ester, monoester into a phosphate ion and an Alcohol (chemistry), alcohol. Because a phosphatase enzyme catalysis, catalyzes the hydrolysis of its Substrate ...

involved in the mating decision of yeast. Ptc1 competes with

Fus3 Fus3 is a MAPK protein involved in the mating decision of yeast. The dissociation of Fus3 from scaffold protein Ste5 results in the switch-like mating decision observed in yeast. During this process, Fus3 competes with a phosphatase Ptc1, attem ...

for control of the 4 phosphorylation sites on the

scaffold protein In biology, scaffold proteins are crucial regulators of many key signalling pathways. Although scaffolds are not strictly defined in function, they are known to interact and/or bind with multiple members of a signalling pathway, tethering them in ...

Ste5 Ste5 is a MAPK scaffold protein involved in the mating of yeast. The active complex is formed by interactions with the MAPK Fus3, the MAPK kinase (MAPKK) Ste7, and the MAPKK kinase Ste11. After the induction of mating by an appropriate mating ph ...

. 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. Ptc1 is also involved in regulating the osmotic stress of yeast, especially via inactivation of Hog1, a member of the

MAPK A mitogen-activated protein kinase (MAPK or MAP kinase) is a type of protein kinase that is specific to the amino acids serine and threonine (i.e., a serine/threonine-specific protein kinase). MAPKs are involved in directing cellular responses to ...

pathway. This inactivation occurred as a result of dephosphorylation of the phosphotheronine but not the phosphotyrosine residue in the phosphorylation lip of Hog1.{{cite journal , last=Warmka , first=Janel , date=Jan 2001 , title= Ptc1, a Type 2C Ser/Thr Phosphatase, Inactivates the HOG Pathway by Dephosphorylating the Mitogen-Activated Protein Kinase Hog1 , journal=Molecular and Cellular Biology , volume=21 , issue=1 , pages=51–60 , doi= 10.1128/MCB.21.1.51-60.2001, pmc=86567 , pmid=11113180 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

Enzymes of known structure