High impact information on PTR3

• Upon detection of external amino acids, Ssy1-Ptr3 likely allows-in a manner dependent on SCF(Grr1)-the Ssy5 endoprotease to gain access to and to cleave Stp1, this requiring prior phosphorylation of Stp1 by casein kinase I [1].
• Mutations in SSY5 manifest phenotypes that are indistinguishable from those resulting from either single ssy1 and ptr3 mutations or ssy5 ssy1 and ssy5 ptr3 double mutations [2].
• Genetic and biochemical analysis of the yeast plasma membrane Ssy1p-Ptr3p-Ssy5p sensor of extracellular amino acids [2].
• Mutations in SSY1 and PTR3 were identified in a genetic selection for components required for the proper uptake and compartmentalization of histidine in Saccharomyces cerevisiae [3].
• Ssy1p requires the endoplasmic reticulum protein Shr3p, the amino acid permease-specific packaging chaperonin, to reach the PM, whereas Ptr3p does not [3].

Biological context of PTR3

• We have found that ssy1 and ptr3 mutants belong to the same epistasis group; single and ssy1 ptr3 double-mutant strains exhibit indistinguishable phenotypes [3].
• Deletion of the PTR3 open reading frame pleiotropically reduced the sensitivity to toxic peptides and amino acid analogues [4].
• SSY1, SSY3 and SSY5 were cloned from a low-copy genomic library by complementation of the mutants [5].
• Constitutive signal transduction by mutant Ssy5p and Ptr3p components of the SPS amino acid sensor system in Saccharomyces cerevisiae [6].

Anatomical context of PTR3

• Ssy1p and Ptr3p are plasma membrane components of a yeast system that senses extracellular amino acids [3].

Associations of PTR3 with chemical compounds

• Mutations in PTR3, BAP2 and SSY1 disrupt sensing and transport of extracellular leucine [7].

Regulatory relationships of PTR3

• PTR3 was required for amino acid-induced expression of PTR2, the gene encoding the dipeptide/tripeptide transport protein, but was not necessary for nitrogen catabolite repression of peptide import or PTR2 expression [4].

Other interactions of PTR3

• The PTR system consists of three genes, PTR1, PTR2 and PTR3 [8].
• However, Stp1 processing does not require SCF(Grr1), Ssy1, or Ptr3 when Ssy5 is overproduced [1].
• Isolation and screening of 31 additional N-methyl-N-nitro-N-Nitrosoguanidine (MNNG)-induced, peptide transport-deficient mutants produced one ptr3 and 30 ptr2 strains: no additional complementation groups were detected [9].
• Two plasma membrane-associated proteins, Ptr3p and Ssy5p, participate in the sensing, which results in cleavage of the transcription factors Stp1p and Stp2p, removing 10 kDa of the N terminus of each of them [6].

References