Disease relevance of CTSE

• Three RNA transcripts (3.6, 2.6, and 2.1 kilobases) were identified in poly(A+) RNA isolated from a gastric adenocarcinoma cell line that produced CTSE that were absent from nonproducing subclones [1].
• The detection frequency of CTSE in the pancreatic juice was significantly higher in the patients with pancreatic ductal adenocarcinoma than in the patients with chronic pancreatitis [2].
• CTSE was also expressed in mucin-producing adenoma, intraductal papillary hyperplasia and mucinous hyperplasia [2].
• Deficiency of cathepsin-E is associated with the development of atopic dermatitis, a pruritic inflammatory skin disease, which has put us to face a high selectivity challenge in the development of drugs for the therapy of Alzheimer's disease or breast cancer [3].
• Accordingly, in the course of finding drugs against Alzheimer's disease or breast cancer by inhibiting BACE1 or cathepsin-D, the desired drugs should selectively inhibit only BACE1 or cathepsin-D, but definitely not cathepsin-E [3].

High impact information on CTSE

• Metaplastic pyloric-type glands expressed pepsinogen II and, except for their expression of cathepsin E, were indistinguishable from normal pyloric glands [4].
• Among 88 such tumors, 93% and 92%, respectively, expressed M1 and cathepsin E, markers of gastric surface-foveolar epithelial cells, 51% expressed pepsinogen II, a marker of gastroduodenal mucopeptic cells, 48% expressed CAR-5, a marker of colorectal epithelial cells, and 35% expressed M3SI, a marker of small intestinal goblet cells [4].
• The last two properties characterize a less-well-known aspartic proteinase, cathepsin E [5].
• Furthermore, the selective degradation of LAMP-1 and LAMP-2, as well as LIMP-2, was also observed by treatment of the lysosomal membrane fraction isolated from wild-type macrophages with purified cathepsin E at pH 5 [6].
• Here we report that cathepsin E deficiency (CatE(-/-)) leads to a novel form of lysosome storage disorder in macrophages, exhibiting the accumulation of the two major lysosomal membrane sialoglycoproteins LAMP-1 and LAMP-2 and the elevation of lysosomal pH [6].

Chemical compound and disease context of CTSE

• We show that thrombin and tryptase cleave HIV-1 gp120 specifically at the tryptic site (GPGR decreases AFVT), and that cathepsin E, an endosomal aspartic proteinase, cleaves at the chymotrypsinlike site (GPGRAF decreases VT) [7].
• Galactose oxidase-Schiff, SH-9 and cathepsin E reactive or positive cancer cells were found in 145 (71.4%), 151 (74.4%) and 144 (70.9%), respectively, of the 203 primary stomach cancers investigated [8].

Biological context of CTSE

• Sequence analysis of CTSE cDNA clones revealed a 1188-base pair open reading frame that exhibited 59% sequence identity with human pepsinogen A. The predicted CTSE amino acid sequence includes a 379-residue proenzyme (Mr = 40,883) and a 17-residue signal peptide [1].
• The CTSE cDNA clones were identified using a set of complementary 18-base oligonucleotide probes specific for a 6-residue sequence surrounding the first active site of all previously characterized human aspartic proteinases [1].
• The CTSE gene was localized to human chromosome 1 by concurrent cytogenetic and cDNA probe analyses of a panel of human x mouse somatic cell hybrids [1].
• Segregation and linkage analysis of two informative restriction fragment length polymorphisms (MspI and DraI) indicated that there is a single human CTSE locus located at chromosome 1q31-q32 which is closely linked to the renin gene [9].
• We suspect that this residue forms an interchain disulfide bond and thereby determines the dimerization of CTSE proenzyme molecules that is observed under native conditions [1].

Anatomical context of CTSE

• The predicted CTSE amino acid composition was consistent with that of purified material from gastric mucosa and gastric adenocarcinoma cell lines [1].
• Three CTSE transcripts (3.6, 2.6, and 2.1 kilobases) were identified in gastric fundic and antral mucosa poly (A+) RNA, and these appeared identical in size and relative abundance to those contained in poly(A+) RNA from cultured gastric adenocarcinoma cell lines containing CTSE [9].
• Pancreatic juice was collected from the patients and subjected to sandwich ELISA and Western analysis for detecting CTSE [2].
• Cathepsin E (CTSE) is a non-secretory, intracellular, but non-lysosomal proteinase found in the highest concentration in the superficial epithelial cells of the stomach [2].
• The aims of our study were to examine the expression of CTSE in the pancreas, to establish an assay system of CTSE and to evaluate the diagnostic usefulness of CTSE in the pancreatic juice [2].

Associations of CTSE with chemical compounds

• The seventh cysteine residue of CTSE is located within the activation peptide region of the proenzyme [1].
• By mutating this residue to alanine, a monomeric form of human cathepsin E was engineered and purified [10].
• The NH2-terminal sequencing revealed that the cathepsin E preparation which had been activated at pH 4.0 contained one major and one minor isozymes in an approximate molar ratio of 3:1 [11].
• In addition, the site of carbohydrate attachment was elucidated by isolation and analysis of a glycopeptide fraction from an enzymatic digest of cathepsin E [11].
• To investigate the function of cathepsin E in processing, a new soluble targeted inhibitor was synthesized by linking the microbial aspartic proteinase inhibitor pepstatin to mannosylated BSA via a cleavable disulfide linker [12].

Enzymatic interactions of CTSE

• By contrast, human cathepsin E specifically cleaved human big endothelin into endothelin1-21 and the C-terminal fragment under identical conditions but did not degrade either product further [13].

Other interactions of CTSE

• Progression-associated gene profiles could be defined (e.g., FABP4 and CTSE) and were already present in the preceding noninvasive papillary tumors [14].
• The effect of alpha 2-macroglobulin, one of the major antiproteinases in the plasma of vertebrates, on the action of the aspartic proteinases chymosin, cathepsin D and cathepsin E towards peptide and protein substrates at pH 6.2 was examined [15].
• Although the overall structures of the three enzymes are quite similar to each other, some subtle difference around their active sites that distinguishes cathepsin-E from cathepsin-D and BACE1 has been revealed through an analysis of hydrogen bond network and microenvironment [3].
• CTSE expression (P = 0.003) and a high Ki-67 labeling index of at least 5% (P = 0.01) were the only factors that correlated significantly with progression-free survival of pTa tumors in our gene expression approach [14].
• In this study we show that cathepsin E, measured at both the protein and message level, is up-regulated late in human B cell activation [16].

Analytical, diagnostic and therapeutic context of CTSE

• Sequence analysis of cDNA clones and comparison with the 3'-flanking untranslated region in genomic clones provided evidence that alternative polyadenylation of the primary transcript resulted in the 2.6- and 2.1-kilobase transcripts which constituted greater than 95% of CTSE transcripts found in the stomach [9].
• Surgically resected pancreatic tissues were subjected to immunohistochemistry for CTSE [2].
• Southern blot analysis of DNA from three independent human x rodent somatic cell hybrids containing X;1 translocations confirmed the assignment of the CTSE gene to the distal region of the long arm of chromosome 1 [17].
• A full length cathepsin E (CTSE) cDNA clone was used to assign the corresponding gene to human chromosome region 1q31 by in situ hybridization [17].
• Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting revealed that the s-CE and v-CE1 consists of two polypeptides of 90 and 84 kDa, whereas v-CE2 is composed of 84- and 82-kDa polypeptides [18].

References