Activation of the Zymogen Form of Prostate-Specific Antigen by Human Glandular Kallikrein 2

Lövgren, Janita; Rajakoski, Kristiina; Karp, Matti; Lundwall, Åke; Lilja, Hans

doi:10.1006/bbrc.1997.7333

Cited by 187 publications

(141 citation statements)

References 24 publications

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“…KLK2 was initially reported as the main activator of pro-KLK3 (22,52,53). However, subsequent reports implied that active KLK2 is unable to cleave the propeptide sequence of KLK3 (21), calling into question the previous finding.…”

Section: Discussionmentioning

confidence: 99%

Human Kallikrein-related Peptidase 14 (KLK14) Is a New Activator Component of the KLK Proteolytic Cascade

Emami¹,

Diamandis²

2008

Journal of Biological Chemistry

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Human kallikrein-related peptidases (KLKs) are a family of 15 serine proteases mainly known for their biomarker utility in various neoplastic and non-neoplastic diseases. Despite significant progress in understanding their clinical application, little is known about the activation mechanism(s) of this important family of enzymes. Emerging evidence indicates that KLKs are activated in a stepwise manner, which is a characteristic of proteolytic cascades. Thus far, KLK cascades have been implicated in semen liquefaction and skin desquamation. Many members of the KLK family have been reported to be active in seminal plasma and/or skin, suggesting their involvement in common proteolytic cascades. KLK14, in particular, is highly active and has recently been proposed as one of the key trypsin-like proteases involved in skin desquamation. This study aims to elucidate a probable cascade-mediated role of KLK14 by 1) examining KLK14-mediated cleavage of a heptapeptide library encompassing activation sites of the 15 KLKs and 2) verifying activation of certain candidate downstream targets of KLK14 (i.e. pro-KLK1, -KLK3, and -KLK11). Heptapeptides encompassing activation motifs of KLK2, -3, -5, and -11 were cleaved with a high (>85%) cleavage efficiency. Activation of these candidates was confirmed using full-length recombinant proteins. Pro-KLK11, -KLK3, and -KLK1 were rapidly activated in a concentration-dependent manner. Pro-KLK3 regulation was bidirectional because activation was followed by inactivation via internal cleavage of active KLK3. We are proposing a putative cascade model, operating through multiple KLKs. Identification of novel members of such proteolytic cascades will aid in further defining mechanisms involved in seminal/skin homeostasis.Proteases are a major group of enzymes participating in a multitude of physiological processes, including coagulation, apoptosis, and immune responses (1). Due to the irreversible nature of proteolytic activation, proteases often remain as inactive zymogens in quiescent conditions. Activation is often triggered by an external stimulus and mediated by highly orchestrated cascades (2). Within a cascade, proteases function coordinately to ensure sequential activation of protease zymogens. The result is a rapid amplification of signal, in response to a minute amount of stimulus (2).Proteolytic cascades are tightly regulated through a series of highly orchestrated feedback loops, internal cleavages, and (auto)degradations. Also, inhibitors play a major role by targeting activated proteases (2). These multiple regulatory points are critical in preventing deleterious effects due to uncontrolled protease activation. Dysregulated protease activation has been implicated in several pathological conditions, such as amyloidogenesis in Alzheimer disease, intravascular coagulation in sepsis, and desquamation in various skin disorders as well as tumor metastasis, invasion, and angiogenesis in cancer (2-5).KLKs 2 belong to a subgroup of secreted serine proteases within the S1 family of clan ...

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Section: Discussionmentioning

confidence: 99%

Human Kallikrein-related Peptidase 14 (KLK14) Is a New Activator Component of the KLK Proteolytic Cascade

Emami¹,

Diamandis²

2008

Journal of Biological Chemistry

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“…7 PSA is expressed as a prepro-protein and exists in several different molecular forms. Pro-PSA is the latent form of the PSA enzyme and has to be activated extracellularly by the action of specific proteases, most probably kallikrein-2, -4 or -5 [8][9][10] The serum PSA test measures total PSA, which consists of all immunodetectable PSA, comprised mostly of free uncomplexed PSA and PSA bound to the protein inhibitor a1-antichymotrypsin (ACT). 11 It also detects pro-PSA, internally cleaved PSA, but not PSA bound to a 2 -macroglobulin.…”

Section: Introductionmentioning

confidence: 99%

PSA affects prostate cancer cell invasion in vitro and induces an osteoblastic phenotype in bone in vivo

Cumming

Hopmans

Vukmirović-Popović

et al. 2011

Prostate Cancer Prostatic Dis

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BACKGROUND:Patients with advanced prostate cancer frequently have a poor prognosis as a result of metastasis and present with high serum PSA levels. There is evidence suggesting that the serine protease activity of PSA could be involved in the invasion and metastasis of prostate cancer. In this study, we determined the effects of PSA and its precursor, pro-PSA, on invasion and the type of bone metastasis. METHODS:We stably transfected prostate adenocarcinoma cells, human DU-145 and rat MatLyLu, with either the fulllength prepro-PSA sequence or pre-PSA DNA, to generate subclones of cells that secrete pro-PSA or free PSA, respectively. Secretion of PSA was measured by western blot analysis and enzyme-linked immunosorbent assay (ELISA). The invasive and migratory properties of the cells were determined using a basement membrane extract and were compared with corresponding empty vector control cells. Twelve days after injection of PSA-secreting MatLyLu cells into the femora of nude mice, bone tumor burden and histomorphometry were determined using a stereological technique. RESULTS:The transfected cells secreted 0.15-2.23 ng PSA/10 6 cells/day. Pro-PSA-secreting subclones increased invasion and migration by 24-263%. Conversely, the PSA-secreting subclones significantly reduced both invasion and migration by 59-70%. The divergent effects on invasion and migration observed in pro-PSA-and PSA-secreting subclones indicate that different forms of PSA may have different functions. Intrafemoral injections with PSA-secreting MatLyLu cells resulted in an increase in osteoblastic parameters when compared with non-PSA-secreting subclones as measured by bone histomorphometry. Concomitantly, a decrease in osteoclasts and eroded surface was observed.CONCLUSIONS: Our in vitro data suggest that PSA, dependent on the predominant form secreted, may decrease or increase invasive properties of prostate cancer cells. The in vivo results indicate that PSA in the bone microenvironment may contribute to the osteoblastic phenotype of bone metastasis frequently observed in prostate cancer.

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“…Specific activity against MeO-suc-Arg-Pro-Tyr-pNA was 100% for sem-KLK3, 70% Brought to you by | MIT Libraries Authenticated Download Date | 5/11/18 6:39 PM for non-glycosylated eco-KLK3, and nearly 100% for yeastexpressed KLK3 variants, which carried either no glycan or a GlcNAc 2 Man 10 tree (Hsieh and Cooperman 2000;Habeck et al, 2001). However, a larger effect of different glycosylation types on substrate turnover cannot be excluded, as observed for mammalian cell (BHK-21) expressed KLK3 that was < 50% active against Lys-Gly-Ile-Ser-Ser-Glu-Tyr-AMC (Lovgren et al, 1997). As the large multi-antennary glycan at Asn61 resides in the prime side region of KLK3 close to the active site, it might interfere with substrate recognition and turnover, especially when larger protein substrates are involved.…”

Section: The Prostatic Klks 2 Andmentioning

confidence: 99%

“…Seminal plasma contains the highest concentration of KLK2, which is thought to be the activator of the semen liquefying KLK3/PSA (Lovgren et al, 1997;Takayama et al, 1997). KLK2 possesses tryptic specificity, cleaves the propeptide APLILSR from KLK3 and may support KLK3 in Structure-based alignment of the mature protease domains of the 15 human KLKs, porcine (pKLK1, pKLK4), horse (eKLK3), rat (rKLK2/ rKLKc2), murine (mKLKb3, mKLK4, mKLK13/mKLKb13) KLKs and bovine chymotrypsin (bCTRA) as numbering reference.…”

Section: The Prostatic Klks 2 Andmentioning

confidence: 99%

Sweetened kallikrein-related peptidases (KLKs): glycan trees as potential regulators of activation and activity

Guo

Skala

Magdolen

et al. 2014

Biological Chemistry

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Most kallikrein-related peptidases (KLKs) are N-glycosylated with N-acetylglucosamine 2 -mannose 9 units at Asn-Xaa-Ser/Thr sequons during protein synthesis and translocation into the endoplasmic reticulum. These N-glycans are modified in the Golgi machinery, where additional O-glycosylation at Ser and Thr takes place, before exocytotic release of the KLKs into the extracellular space. Sequons are present in all 15 members of the KLKs and comparative studies for KLKs from natural and recombinant sources elucidated some aspects of glycosylation. Although glycosylation of mammalian KLKs 1, 3, 4, 6, and 8 has been analyzed in great detail, e.g., by crystal structures, the respective function remains largely unclear. In some cases, altered enzymatic activity was observed for KLKs upon glycosylation. Remarkably, for KLK3/PSA, changes in the glycosylation pattern were observed in samples of benign prostatic hyperplasia and prostate cancer with respect to healthy individuals. Potential functions of KLK glycosylation in structural stabilization, protection against degradation, and activity modulation of substrate specificity can be deduced from a comparison with other glycosylated proteins and their regulation. According to the new concept of protein sectors, glycosylation distant from the active site might significantly influence the activity of proteases. Novel pharmacological approaches can exploit engineered glycans in the therapeutical context.

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Activation of the Zymogen Form of Prostate-Specific Antigen by Human Glandular Kallikrein 2

Cited by 187 publications

References 24 publications

Human Kallikrein-related Peptidase 14 (KLK14) Is a New Activator Component of the KLK Proteolytic Cascade

Human Kallikrein-related Peptidase 14 (KLK14) Is a New Activator Component of the KLK Proteolytic Cascade

PSA affects prostate cancer cell invasion in vitro and induces an osteoblastic phenotype in bone in vivo

Sweetened kallikrein-related peptidases (KLKs): glycan trees as potential regulators of activation and activity

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