| 1. |
- Abdrakhmanov, A, et al.
(författare)
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Involvement of mitophagy in cisplatin-induced cell death regulation
- 2019
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Ingår i: Biological chemistry. - : Walter de Gruyter GmbH. - 1437-4315 .- 1431-6730. ; 400:2, s. 161-170
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Tidskriftsartikel (refereegranskat)abstract
- Mitophagy, the selective degradation of mitochondria via the autophagic pathway, is a vital mechanism of mitochondrial quality control in cells. The removal of malfunctioning or damaged mitochondria is essential for normal cellular physiology and tissue development. Stimulation of mitochondrial permeabilization and release of proapoptotic factors from the intermembrane space is an essential step in triggering the mitochondrial pathway of cell death. In this study, we analyzed the extent to which mitophagy interferes with cell death, attenuating the efficiency of cancer therapy. We show that stimulation of mitophagy suppressed cisplatin-induced apoptosis, while mitophagy inhibition stimulates apoptosis and autophagy. Suppression of mitophagy involved production of reactive oxygen species, and the fate of cell was dependent on the interplay between endoplasmic reticulum stress and autophagy.
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| 2. |
- Appelros, Stefan, et al.
(författare)
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Studies on the turnover of procarboxypeptidase B, its active enzyme and the activation peptide in the pig
- 1998
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Ingår i: Biological Chemistry. - : Walter de Gruyter GmbH. - 1437-4315. ; 379:7, s. 893-898
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Tidskriftsartikel (refereegranskat)abstract
- Recent developments in the treatment of acute pancreatitis have focused on the importance of early determination of the severity of an attack. Measuring levels of activation peptides from pancreatic proenzymes seems to be one way to predict severity. Levels of the activation peptide from procarboxypeptidase B, in both serum and urine on admission, have been shown to correlate to the outcome. To be able to interpret levels of this peptide in serum and urine under normal and in various acute abdominal conditions, we need knowledge about its turnover in the circulation. Procarboxypeptidase B, active carboxypeptidase and the activation peptide were therefore purified from porcine pancreatic juice. These proteins were labelled with 125I or 131I and their turnovers were studied in vivo in the pig. The proenzyme and the activation peptide were eliminated without interaction with any substance in the circulation. The active enzyme was to some degree bound to a substance with a molecular mass of 10-20 kDa. Active CPB was eliminated more slowly than proCPB and the activation peptide. Five percent of the activation peptide was detected nondegraded in the urine. After intraduodenal administration of the activation peptide there was no sign of the peptide in the urine.
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| 3. |
- Arampatzidou, Maria, et al.
(författare)
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Effects of cathepsin K deficiency on intercellular junction proteins, luminal mucus layers, and extracellular matrix constituents in the mouse colon.
- 2012
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Ingår i: Biological chemistry. - : Walter de Gruyter GmbH. - 1437-4315. ; 393:12, s. 1391-403
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Tidskriftsartikel (refereegranskat)abstract
- Cathepsin K has been shown to exhibit antimicrobial and anti-inflammatory activities in the mouse colon. To further elucidate its role, we used Ctsk-/- mice and demonstrated that the absence of cathepsin K was accompanied by elevated protein levels of related cysteine cathepsins (cathepsins B, L, and X) in the colon. In principle, such changes could result in altered subcellular localization; however, the trafficking of cysteine cathepsins was not affected in the colon of Ctsk-/- mice. However, cathepsin K deficiency affected the extracellular matrix constituents, as higher amounts of collagen IV and laminin were observed. Moreover, the localization pattern of the intercellular junction proteins E-cadherin and occludin was altered in the colon of Ctsk-/- mice, suggesting potential impairment of the barrier function. Thus, we used an ex vivo method for assessing the mucus layers and showed that the absence of cathepsin K had no influence on mucus organization and growth. The data of this study support the notion that cathepsin K contributes to intestinal homeostasis and tissue architecture, but the lack of cathepsin K activity is not expected to affect the mucus-depending barrier functions of the mouse colon. These results are important with regard to oral administration of cathepsin K inhibitors that are currently under investigation in clinical trials.
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| 4. |
- Aspenstrom, P
(författare)
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Atypical Rho GTPases RhoD and Rif integrate cytoskeletal dynamics and membrane trafficking
- 2014
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Ingår i: Biological chemistry. - : Walter de Gruyter GmbH. - 1437-4315 .- 1431-6730. ; 395:5, s. 477-484
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Tidskriftsartikel (refereegranskat)abstract
- The Rho GTPases are essential regulators of basic cellular processes, including cell migration, cell contraction and cell division. Most studies still involve just the three canonical members, RhoA, Rac1 and Cdc42, although the Rho GTPases comprise at least 20 members. The aim of this review is to highlight some of the recent advances in our knowledge regarding the less-studied Rho members, with the focus on RhoD and Rif. The phenotypic alterations to cell behaviour that are triggered by RhoD and Rif suggest that they have unique impacts on cytoskeletal dynamics that distinguish them from the well-studied members of the Rho GTPases. In addition, RhoD has a role in the regulation of intracellular transport of vesicles. Taken together, the available data indicate that RhoD and Rif have functions as master regulators in the integration of cytoskeletal reorganisation and membrane trafficking.
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| 5. |
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| 6. |
- Bjorkqvist, J, et al.
(författare)
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Zinc-dependent contact system activation induces vascular leakage and hypotension in rodents
- 2013
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Ingår i: Biological chemistry. - : Walter de Gruyter GmbH. - 1437-4315. ; 394:9, s. 1195-1204
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Tidskriftsartikel (refereegranskat)abstract
- Contact to polyanions induces autoactivation of the serine protease factor XII that triggers the kallikrei-kinin system. Recent studies indicate that polysaccharide-induced autoactivation of factor XII has a role in allergy-related vascular leakage, and angioedema. Here, we characterize in vivo effects of the synthetic polysaccharide dextran sulfate in human plasma and in rodent models. Minute amounts of high-molecular-weight dextran sulfate-initiated factor XII-autoactivation and triggered formation of the inflammatory mediator bradykinin via plasma kallikrein-mediated cleavage of high-molecular-weight kininogen. High-molecular-weight kininogen fragments, containing the HKH20 sequence in domain D5H, blocked dextran sulfate-initiated bradykinin-generation by depleting plasma Zn2+ ions. Topical application of high molecular weight dextran sulfate increased leakage in murine skin microvessels, in a bradykinin-dependent manner. Intravital laser scanning microscopy showed a greater than two-fold elevated and accelerated fluid extravasation in C1 esterase inhibitor deficient mice that lack the major inhibitor of factor XII, compared to wild-type controls. Intra-arterial infusion of dextran sulfate induced a rapid transient drop in arterial blood pressure in rats and preinjection of kinin B2 receptor antagonists or HKH20 peptide blunted dextran sulfate-triggered hypotensive reactions. The data characterize dextran sulfate as a potent in vivo activator of factor XII with implications for bradykinin-mediated vascular permeability and blood pressure control.
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| 7. |
- Brännström, Kristoffer, et al.
(författare)
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Characterization of SPINK9, a KLK5-specific inhibitor expressed in palmo-plantar epidermis
- 2012
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Ingår i: Biological chemistry (Print). - : Walter de Gruyter. - 1431-6730 .- 1437-4315. ; 393:5, s. 369-377
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Tidskriftsartikel (refereegranskat)abstract
- SPINK9, a Kazal-type serine protease inhibitor, is almost exclusively expressed in the palmo-plantar epidermis. SPINK9 selectively inhibits kallikrein-related peptidase 5 (KLK5), no other target enzyme is known at present. In this study, we defined the reactive loop to residues 48 and 49 of SPINK9 and characterized the inhibition and binding of different SPINK9 variants towards KLK5, KLK7, KLK8 and KLK14. Substitutions of single amino acids in the reactive loop had a large impact on both inhibitory efficiency and specificity. Binding studies showed that it is mainly the dissociation rate that is affected by the amino acid substitutions. The inhibitory effect of wild-type SPINK9 was clearly pH-dependent with an improved effect at a pH similar to that of the outer layers of the skin. Modeling of the enzyme-inhibitor complexes showed that the reactive loop of SPINK9 fits very well into the deep negatively charged binding pocket of KLK5. A decrease in pH protonates His48 of the wild-type protein resulting in a positively charged residue, thereby explaining the observed decreased dissociation rate. Interestingly, substitution with a positively charged amino acid at position 48 resulted in a more efficient inhibitor at higher pH.
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| 8. |
- de Veer, Simon J., et al.
(författare)
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Exploring the active site binding specificity of kallikrein-related peptidase 5 (KLK5) guides the design of new peptide substrates and inhibitors
- 2016
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Ingår i: Biological chemistry (Print). - : Walter de Gruyter GmbH. - 1431-6730 .- 1437-4315. ; 397:12, s. 1237-1249
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Tidskriftsartikel (refereegranskat)abstract
- Kallikrein-related peptidase 5 (KLK5) is a promising therapeutic target in several skin diseases, including Netherton syndrome, and is emerging as a potential target in various cancers. In this study, we used a sparse matrix library of 125 individually synthesized peptide substrates to characterize the binding specificity of KLK5. The sequences most favored by KLK5 were GRSR, YRSR and GRNR, and we identified sequence-specific interactions involving the peptide N-terminus by analyzing kinetic constants (k(cat) and K-M) and performing molecular dynamics simulations. KLK5 inhibitors were subsequently engineered by substituting substrate sequences into the binding loop (P1, P2 and P4 residues) of sunflower trypsin inhibitor-1 (SFTI-1). These inhibitors were effective against KLK5 but showed limited selectivity, and performing a further substitution at P2' led to the design of a new variant that displayed improved activity against KLK5 (K-i = 4.2 +/- 0.2 nm), weak activity against KLK7 and 12-fold selectivity over KLK14. Collectively, these findings provide new insight into the design of highly favored binding sequences for KLK5 and reveal several opportunities for modulating inhibitor selectivity over closely related proteases that will be useful for future studies aiming to develop therapeutic molecules targeting KLK5.
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| 9. |
- Ellencrona, Karin, et al.
(författare)
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Flavivirus NS5 associates with host-cell proteins zonula occludens-1 (ZO-1) and regulating synaptic membrane exocytosis-2 (RIMS2) via an internal PDZ binding mechanism
- 2009
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Ingår i: Biological chemistry (Print). - Berlin : Walter de Gruyter. - 1431-6730 .- 1437-4315. ; 390:4, s. 319-323
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Tidskriftsartikel (refereegranskat)abstract
- Dengue virus (DENV) and tick-borne encephalitis virus (TBEV) are flaviviruses, which can cause lethal hemorrhagic fever and encephalitis, respectively. Here, we demonstrate that the TBEV-NS5 and DENV-NS5 proteins use an internal binding mechanism to target human PDZ proteins. TBEV-NS5 has high affinity to regulating synaptic membrane exocytosis-2 (RIMS2) and Scribble, whereas DENV-NS5 binds primarily to the tight junction protein zonula occludens-1 (ZO-1). Targeting of TBEV-NS5 to the plasma membrane is stabilised by ZO-1; however, DENV-NS5 co-localises with ZO-1 in the nucleus. These interactions have potential important roles in the ability of flaviviruses to manipulate cell proliferation, junction permeability and the interferon pathways.
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| 10. |
- Faroldi, Gianni, et al.
(författare)
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ADAMTS: Novel proteases expressed by activated mast cells
- 2013
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Ingår i: Biological Chemistry. - : Walter de Gruyter GmbH. - 1431-6730 .- 1437-4315. ; 394, s. 291-305
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Tidskriftsartikel (refereegranskat)abstract
- Here we show that mast cells (MCs) express the metalloproteases of the A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, and that ADAMTS expression is influenced by MC activation. Co-culture of MCs with live Gram-positive bacteria caused a profound induction of ADAMTS-9 and -6, as well as down-regulated expression of ADAMTS-5. Similar patterns were also seen after MC activation with calcium ionophore and by immunoglobulin E receptor crosslinking. Moreover, ADAMTS-5, -6 and -9 were all induced by activation of terminally differentiated murine peritoneal MCs and in a human MC line. ADAMTS-9 up-regulation in response to immunoglobulin E receptor crosslinking was strongly dependent on Go6976-sensitive protein kinase C and partly dependent on nuclear factor of activated T cells and nuclear factor kappa-light-chain-enhancer of activated B cells, respectively. The expression of ADAMTS-5, -6 and -9 was closely linked to MC maturation, as shown by their strong induction during the differentiation of bone marrow precursor cells into mature MCs. ADAMTS family members have been shown to possess aggrecanase activity. Accordingly, MCs were shown to express aggrecanase activity. Finally, ADAMTS-5 protein was detected in MCs by immunocytochemistry. Taken together, the present study reveals ADAMTS expression by MCs and that MC activation regulates the expression of these proteases, thus implicating the ADAMTS family of proteases in MC function.
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