Volume 389, Issue 12

The genes encoding the kininogenase, glandular tissue kallikrein, in rodents and man were first described in the mid-1980s. Remarkably, they appeared to be part of a much larger highly conserved family of genes ( GK ) in rodents, but only had two paralogs in man. This discrepancy was not rectified until the late 1990s/2000 with the identification of a cluster of 12 more kallikrein-related ( KLK ) genes in the human 19q13 locus and the subsequent identification of their rodent homologs. Interestingly, there are remarkable similarities in expression patterns, hormonal regulation and functional attributes of the old ( GK ) and new ( KLK ) families which underscore the evolutionary conservation across these loci and species. This historical perspective focuses on the lessons learned from earlier studies on the rodent GK gene families and the striking similarities of some attributes, yet uniqueness, of others. These earlier findings have all contributed to the current status of the KLK serine peptidase-encoding gene family as an exciting source of new biomarkers and therapeutic targets.

Several neurodegenerative diseases, including Kennedy's disease (KD), are associated with misfolding and aggregation of polyglutamine (polyQ)-expansion proteins. KD is caused by a polyQ-expansion in the androgen receptor (AR), a key player in male sexual differentiation. Interestingly, KD patients often show signs of mild-to-moderate androgen insensitivity syndrome (AIS) resulting from AR dysfunction. Here, we used the yeast Saccharomyces cerevisiae to investigate the molecular mechanism behind AIS in KD. Upon expression in yeast, polyQ-expanded N-terminal fragments of AR lacking the hormone binding domain caused a polyQ length-dependent growth defect. Interestingly, while AR fragments with 67 Q formed large, SDS-resistant inclusions, the most pronounced toxicity was observed upon expression of 102 Q fragments which accumulated exclusively as soluble oligomers in the 100–600 kDa range. Analysis using a hormone-dependent luciferase reporter revealed that full-length polyQ-expanded AR is fully functional in transactivation, but becomes inactivated in the presence of the corresponding polyQ-expanded N-terminal fragment. Furthermore, the greatest impairment of AR activity was observed upon interaction of full-length AR with soluble AR fragments. Taken together, our results suggest that soluble polyQ-containing fragments bind to full-length AR and inactivate it, thus providing insight into the mechanism behind AIS in KD and possibly other polyglutamine diseases, such as Huntington's disease.

Apoptosis is a tightly regulated process that plays a critical role in many biological events. Members of the BCL2 ( Bcl-2 ) family of apoptosis-related genes have been found to be differentially expressed in various malignancies and have been proposed as prognostic tumor biomarkers. We have recently discovered and cloned a new member of the BCL2 gene family, BCL2L12 , expressed in colon tissues. Here we have investigated expression of the BCL2L12 gene in colon cancer tissues and assessed its prognostic value. Total RNA was isolated from 96 specimens of malignant colon tissue. After testing the RNA quality, cDNA was prepared by reverse transcription. A highly sensitive real-time PCR method for BCL2L12 mRNA quantification was developed using SYBR ® Green chemistry. GAPDH served as a housekeeping gene. Relative quantification analysis was performed using the comparative C T method (2 -ΔΔCT ). High BCL2L12 expression levels were found in smaller (≤5 cm, p =0.027) and well-differentiated tumors ( p =0.034), as well as in early-stage tumors ( p =0.039). Survival analysis demonstrated that patients with BCL2L12 -positive colon tumors have significantly longer disease-free survival and overall survival ( p =0.015 and p =0.027, respectively). Our results suggest that BCL2L12 gene expression may represent a potential new biomarker for colon cancer.

Angiotensin-converting enzyme (ACE) demonstrates, besides its typical dipeptidyl-carboxypeptidase activity, several unusual functions. Here, we demonstrate with molecular, biochemical, and cellular techniques that the somatic wild-type murine ACE (mACE), stably transfected in Chinese Hamster Ovary (CHO) or Madin-Darby Canine Kidney (MDCK) cells, interacts with endogenous membranal co-localized carboxypeptidase M (CPM). CPM belongs to the group of glycosylphosphatidylinositol (GPI)-anchored proteins. Here we report that ACE, completely independent of its known dipeptidase activities, has GPI-targeted properties. Our results indicate that the spatial proximity between mACE and the endogenous CPM enables an ACE-evoked release of CPM. These results are discussed with respect to the recently proposed GPI-ase activity and function of sperm-bound ACE.

The S 1 ′ and S 2 ′ subsite specificities of human tissue kallikrein 1 (KLK1) and human plasma kallikrein (HPK) were examined with the peptide series Abz-GFSPFRXSRIQ-EDDnp and Abz-GFSPFRSXRIQ-EDDnp [X=natural amino acids or S(PO 3 H 2 )]. KLK1 efficiently hydrolyzed most of the peptides except those containing negatively charged amino acids at P 1 ′ and P 2 ′ positions. Abz-GFSPFRSSRIQ-EDDnp, as in human kininogen, is the best substrate for KLK1 and exclusively cleaved the R-S bond. All other peptides were cleaved also at the F-R bond. The synthetic human kininogen segment Abz-MISLMKRPPGFSPFRS 390 S 391 RI-NH 2 was hydrolyzed by KLK1 first at R-S and then at M-K bonds, releasing Lys-bradykinin. In the S 390 and S 391 phosphorylated analogs, this order of hydrolysis was inverted due to the higher resistance of the R-S bond. Abz-MISLMKRPPG-FSPFRSS(PO 3 H 2 ) 391 RI-NH 2 was hydrolyzed by KLK1 at M-K and mainly at the F-R bond, releasing des-(Arg 9 )-Lys-Bk which is a B1 receptor agonist. HPK cleaved all the peptides at R and showed restricted specificity for S in the S 1 ′ subsite, with lower specificity for the S 2 ′ subsite. Abz-MISLMKRPPGFSPFRSSRI-NH 2 was efficiently hydrolyzed by HPK under bradykinin release, while the analogs containing S(PO 3 H 2 ) were poorly hydrolyzed. In conclusion, S 1 ′ and S 2 ′ subsite specificities of KLK1 and HPK showed peculiarities that were observed with substrates containing the amino acid sequence of human kininogen.

Here, we describe a novel member in the group of membrane-anchored chymotrypsin (S1)-like serine proteases, namely testis serine protease 1 (T-SP1), as it is principally expressed in testis tissue. The human T-SP1 gene encompasses 28.7 kb on the short arm of chromosome 8 and consists of seven exons. Rapid amplification of cDNA ends (RACE) experiments revealed that due to alternative splicing three different variants (T-SP1/1, -2, -3) are detectable in testis tissue displaying pronounced heterogeneity at their 3′-end. T-SP1/1 consists of an 18 amino acid signal peptide and of a 49 amino acid propeptide. The following domain with the catalytic triad of His 108 , Asp 156 , and Ser 250 shares sequence identities of 42% and 40% with the blood coagulation factor XI and plasma kallikrein, respectively. Only T-SP1/1 contains a hydrophobic part at the C-terminus, which provides the basis for cell membrane anchoring. Using a newly generated polyclonal anti-T-SP1 antibody, expression of the T-SP1 protein was found in the Leydig and Sertoli cells of the testis and in the epithelial cells of the ductuli efferentes. Notably, T-SP1 protein was also detectable in prostate cancer and in some ovarian cancer tissues, indicating tumor-related synthesis of T-SP1 beyond testis tissue.

The calpain inhibitor A-705253 and the Na + /H + -exchange inhibitor Cariporide ® were studied in isolated perfused rabbit hearts subjected to 60 min occlusion of the ramus interventricularis of the left coronary artery (below the origin of the first diagonal branch), followed by 120 min of reperfusion. The inhibitors were added to the perfusion fluid solely or in combination at the beginning of reperfusion. Hemodynamic monitoring and biochemical analysis of perfusion fluid from the coronary outflow were performed. Myocardial infarct size and area at risk (transiently not perfused myocardium) were determined from left ventricular slices after a special staining procedure with Evans blue and 2,3,5-triphenyltetrazolium chloride. The infarcted area (dead myocardium) was 72.7±4.0% of the area at risk in untreated controls, but was significantly smaller in the presence of the inhibitors. The largest effect was observed with 10 -6  M A-705253, which reduced the infarcted area to 49.2±4.1% of the area at risk, corresponding to a reduction of 33.6%. Cariporide ® at 10 -6  M reduced the infarct size to the same extent. The combination of both inhibitors, however, did not further improve cardioprotection. No significant difference was observed between the experimental groups in coronary perfusion, left ventricular pressure, heart rate, or in the release of lactate dehydrogenase and creatine kinase from heart muscle.

Human tissue kallikrein-related peptidases (KLKs) are 15 hormonally regulated genes on chromosome 19q13.4 encoding secreted serine proteases. Many KLKs are expressed throughout the female reproductive system and found in cervico-vaginal fluid (CVF). Immunohistochemistry was performed to determine KLK localization in the female reproductive system (fallopian tube, endometrium, cervix and vagina tissues). KLK levels were measured in CVF and saliva over the menstrual cycle to study whether KLKs are regulated by hormonal changes during the cycle. In vitro cleavage analysis was performed to establish whether KLKs may play a role in vaginal epithelial desquamation, mucus remodeling or processing of antimicrobial proteins. KLKs were localized in the glandular epithelium of the fallopian tubes and endometrium, the cervical mucus-secreting epithelium and vaginal stratified squamous epithelium. KLK levels peaked in CVF and saliva after ovulation. In vitro cleavage analysis confirmed KLKs 5 and 12 as capable of digesting desmoglein and desmocollin adhesion proteins and cervical mucin proteins 4 and 5B. KLK5 can digest defensin-1α, suggesting it may aid in cervico-vaginal host defense. We provide evidence of potential physiological roles for KLKs in cervico-vaginal physiology: in desquamation of vaginal epithelial cells, remodeling of cervical mucus and processing of antimicrobial proteins.

A range of various assays to measure chemosusceptibility of Plasmodium falciparum have been described in the literature. As the screening of a plethora of compounds for antiplasmodial activity is urgently needed and becomes a constantly increasing routine analysis, a test system has to fulfill the following requirements: sensitivity, reliability, simplicity of performance, high-throughput compatibility, and cost-effectiveness. Here, we describe an assay that fulfills all criteria and in which the fluorescent SYTOX ® Green dye is introduced to determine growth inhibition of Plasmodia in in vitro cultures.

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