Disease relevance of YPS1

• Yapsin null mutants show hypersensitivity to cell wall perturbation, and both the yps1Delta2Delta mutant and the quintuple yapsin mutant (5ypsDelta) undergo osmoremedial cell lysis at 37 degrees C. The cell walls of both 5ypsDelta and yps1Delta2Delta mutants have decreased amounts of 1,3- and 1,6-beta-glucan [1].

High impact information on YPS1

• MKC7 encodes an aspartyl protease most closely related to product of the YAP3 gene, a previously isolated multicopy suppressor of the pro-alpha-factor processing defect of a kex2 null [2].
• N-terminal amino acid sequence analysis yielded two sequences indicating that Sap9p is composed of two subunits, designated here as alpha and beta, similar to yapsin 1 [3].
• Yap3p, a well characterized GPI-anchored plasma membrane aspartic protease, was localized in the cell wall when the omega-minus region was mutated to sequences containing Val or Ile at the omega-4 or -5 site and Val or Tyr at the omega-2 site [4].
• The activation of proyapsin 1 in vitro exhibited linear kinetics and generated an intermediate form of yapsin 1 or pseudo-yapsin 1 [5].
• The yeast YAP3 gene encodes an aspartyl endoprotease that cleaves precursor proteins at selected pairs of basic amino acids and after single arginine residues [6].

Biological context of YPS1

• The Candida albicans (SAP9) and Candida glabrata (CgYPS1) homologues of YPS1 complement the phenotypes of the yps1Delta mutant [1].
• The different substrate specificities of both proteases and their mutual redundancy for propeptide processing indicate that P. pastoris kex2 and yps1 single-gene disruptants can be used for the alpha-factor leader-directed secretion of heterologous proteins otherwise degraded at basic residues [7].
• The corresponding gene YAP3 was located to chromosome XII [8].
• Molecular modeling of yapsin 1 identified the active-site cleft to have negative residues close to or within the S6, S3, S2, S1, S1', S2', and S3' pockets and is more electronegative than rhizopuspepsin or endothiapepsin [9].
• Treatment of YAP3p with endoglycosidase H reduced the size of both forms of the protein to approximately 65 kDa, consistent with the presence of 10 potential N-linked glycosylation sites in the deduced amino acid sequence of this protein [10].

Anatomical context of YPS1

• The results we report here are not in agreement with such a model as we show that constructs containing the C-terminal parts of Gas1p and Yap3p are also targeted to the cell wall [11].
• Vacuolar Yps1 caused degradation of a mammalian sialyltransferase ectodomain fusion protein (ST6Ne), which was directed from the Golgi to the vacuole in both normal and Delta erg6 cells [12].
• The yeast proprotein convertase encoded by YAP3 is a glycophosphatidylinositol-anchored protein that localizes to the plasma membrane [6].
• Furthermore, consistent with the transport of Yap3 to the plasma membrane, the endoprotease sediments with secretory vesicles which accumulate at restrictive temperature in the late secretory mutant sec1-1 [6].
• Treatment of the total yeast membranes with chemical agents known to disrupt protein-protein and protein-lipid interactions reveal that Yap3 is membrane-associated [6].

Associations of YPS1 with chemical compounds

• Our results show that both endoproteases generate mature SRIF-28 from prosomatostatin-II but that only Yap3 can process the homologous monobasic cleavage site (ie single arginine residue) found in prosomatostatin-I [13].
• An altered form of APP-695, in which glutamine replaced Lys-612 at the cleavage site, is cleaved by Yap3 at 5% the rate of the wild-type APP [14].
• YAP3 was purified to apparent homogeneity using concanavalin A and pepstatin A affinity chromatography [15].
• In both differential centrifugation of intracellular organelles and sucrose density gradients, the bulk of Yap3 at steady state co-localizes with the plasma membrane azide-insensitive ATPase [6].
• Cleavage by yapsin 1 occurred C-terminal to a subset of single lysine residues [16].

Other interactions of YPS1

• Reduced proteolysis of secreted gelatin and Yps1-mediated alpha-factor leader processing in a Pichia pastoris kex2 disruptant [7].
• Identification and characterization of Saccharomyces cerevisiae yapsin 3, a new member of the yapsin family of aspartic proteases encoded by the YPS3 gene [17].
• Sequence analysis of a 37.6 kbp cosmid clone from the right arm of Saccharomyces cerevisiae chromosome XII, carrying YAP3, HOG1, SNR6, tRNA-Arg3 and 23 new open reading frames, among which several homologies to proteins involved in cell division control and to mammalian growth factors and other animal proteins are found [18].
• Based upon the release of the membrane-bound form by bacterial phosphatidylinositol phospholipase C digestion and metabolic labeling of the protein with myo-[3H]inositol, Yap3 owes its association with the membrane to the addition of a glycophosphatidylinositol anchor [6].

Analytical, diagnostic and therapeutic context of YPS1

• A C-terminally truncated form of yapsin 1 (yeast aspartic protease 3) was overexpressed in yeast and its processing through the secretory pathway was followed by pulse-labeling and immunoprecipitation studies [19].
• Western blot analysis after sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed two secreted forms of YAP3p with apparent molecular masses of approximately 180 and approximately 90 kDa [10].
• YAP3p has an isoelectric point of approximately 4.5 as determined by isoelectric focusing gel electrophoresis [10].
• In the bovine intermediate pituitary, a subpopulation of cells was intensely stained with the YAP3p antiserum, and in combination with in situ hybridization, these cells were shown to contain POMC messenger RNA (mRNA) [20].

References