Disease relevance of CPS1

• Salmonella flagellar hook protein and yeast carboxypeptidase S [1].
• For the direct identification of Escherichia coli, sensitivities were 93.8%, 88.5%, 86.1% and 82.2% for CHROMagar Orientation, CPS ID2, UriSelect3 and Rainbow UTI, respectively [2].
• Tests carried out by using three new media from bioMérieux are described: CPS ID 2 to detect and identify Escherichia coli, Proteus and Enterococcus; SMID to detect Salmonella; and Albicans ID to isolate yeast and identify Candida albicans [3].

High impact information on CPS1

• We have identified a transmembrane ubiquitin ligase, Tul1, that is resident in the Golgi apparatus and is required for the ubiquitination of proteins with polar TMDs, including vacuolar proteins such as carboxypeptidase S [4].
• Consistent with ALP following an alternative route to the vacuole, isolation of a vps41tsf mutant revealed that at non-permissive temperature ALP is mislocalized while vacuolar delivery of CPS and CPY is maintained [5].
• Given the demonstrated role of t-SNAREs such as Pep12p in transport vesicle recognition, our results indicate that ALP and CPS are packaged into distinct transport intermediates [5].
• Deletion of VTA1 did not affect growth on raffinose and only mildly affected carboxypeptidase S sorting [6].
• Multivesicular body sorting: ubiquitin ligase Rsp5 is required for the modification and sorting of carboxypeptidase S [7].

Biological context of CPS1

• Furthermore, a 162 bp fragment spanning positions -644 to -482 of the promoter of the CPS1 gene repressed gene expression when placed 3' to the upstream activation sequence (UAS) of the heterologous gene CYC1 [8].
• The open reading frame of CPS1 consists of 576 codons and therefore encodes a protein of 64961 molecular weight [9].
• A transcriptional activation of CPS1 occurs when cells grow on a substrate of carboxy-peptidase yscS as sole nitrogen source [9].
• CPS1 was determined by DNA blot analysis to be a single copy gene located on chromosome X. The cloned fragment was used to identify a 2.1 kb mRNA [9].

Anatomical context of CPS1

• Precursor forms of vacuolar proteins with transmembrane domains, such as the carboxypeptidase S Cps1p and the polyphosphatase Phm5p, are selectively sorted in endosomal compartments to vesicles that invaginate, budding into the lumen of the late endosomes, resulting in the formation of multivesicular bodies (MVBs) [10].
• The more modestly polar transmembrane domains of Sec12p and Ufe1p, which normally serve to hold these proteins in the endoplasmic reticulum, also cause Pep12p to be internalized, as does that of the vacuolar protein Cps1p [11].

Associations of CPS1 with chemical compounds

• In addition, at least three other upstream activation UASs responsible for the activation of CPS1 expression by glucose under nitrogen starvation conditions were found to be located between positions -673 and -644, -482 and -353, and -243 and -186, respectively [8].
• Non-metabolizable sugar analogs (2-deoxyglucose, 6-methyl-glucose or glucosamine) do not allow derepression of CPS1, showing that the process is energy-dependent [12].
• Transfer of ammonium-glucose pre-grown cells to a medium deprived of nitrogen causes a drastic increase in CPS1 RNA level provided that a readily usable carbon source, such as glucose or fructose, is available to the cells [12].
• Neither glycerol, ethanol, acetate nor galactose support derepression of CPS1 expression under nitrogen starvation conditions [12].
• The cloned CPS1 gene, which again enabled a leucine auxotrophic cps1-3 mutant to grow on the modified dipeptide Cbz-Gly-Leu (Cbz, benzyloxycarbonyl) as sole leucine source, was sequenced and found to consist of an open reading frame of 1728 bp encoding a protein of 576 amino acids [13].

Physical interactions of CPS1

• Surprisingly, strains harboring chc1-5 exhibited a significant defect in transport of carboxypeptidase Y or carboxypeptidase S to the vacuole that was not observed in other chc1 ts mutants [14].

Other interactions of CPS1

• Ubiquitylation of Cps1p was strongly reduced in the npi1 mutant strain and ubiquitylation was completely abolished in the npi1 tul1Delta double mutant [10].
• Using mutant strain ABYS1 of Saccharomyces cerevisiae lacking four main vacuolar proteinases, proteinase A, proteinase B, carboxypeptidase Y, and carboxypeptidase S, we examined the identities of chromatin-associated proteinases, ruling out possible contamination of the chromatin fraction by them [15].

Analytical, diagnostic and therapeutic context of CPS1

• A roughly 130-kDa protein which was found to cross-react with an anti-rat CPS antibody in Western blots (immunoblots) was observed [16].

References