Phospholipase C from Bacillus cereus and Its Use in Studies of Tissue Thromboplastin

Otnaess, A B; Prydz, Hans; Bjørklid, Eirik; Berre, Åse Gladhaug

doi:10.1111/j.1432-1033.1972.tb01832.x

Cited by 90 publications

(23 citation statements)

References 17 publications

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“…The thrombinenhanced PCA was inhibited by phospholipase C and was not expressed when tested in factor VII-deficient plasma, thus confirning that the up-regulated PCA was due to the enhanced TF activity of SW-480 cells. This is consistent with the previous observation that close association with certain membrane phospholipids is essential for the functional activity of TF, as phospholipase C tratment destroyed procoagulant activity of TF in monocytes and renal glomeruli (Otnaess et al 1972;Komberg et al, 1994;Tipping et al, 1998). The time-and dose-dependent manner of thrombin in enhancing PCA suggests a thrombin receptor-mediated mode of action, but the identification of the receptors and their role in mediating thrombin-enhanced TF activity are not known.…”

Section: Discussionsupporting

confidence: 90%

Tissue factor activity of SW-480 human colon adenocarcinoma cells is modulated by thrombin and protein kinase C activation

Chiang

Yang²,

Lin³

et al. 1998

Br J Cancer

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Summary Expression of tissue factor (TF), a cellular initiator of the extrinsic coagulation cascade, is a feature of many malignant tumours and is intimately involved in the process of metastasis. SW-480 human colon adenocarcinoma cells responded to thrombin (1 U mM') or phorbol 12-myristate 13-acetate (PMA, 0.1 rM) with a 6.0-fold and a 7.7-fold increase in their procoagulant activity (PCA), respectively, after 4-6 h incubation in serum-free medium. The thrombin-enhanced PCA was significantly inhibited by complexing of thrombin with hirudin, or by senne protease inhibition with 3,4-dichloroisocoumarin. Both effects of thrombin and PMA on PCA in SW-480 cells were blocked by pretreatment of cells with cycloheximide or actinomycin D, indicating that the response required de novo protein and RNA synthesis. The thrombin-enhanced PCA depended on the activation of protein kinase C (PKC) as it was diminished by staurosponne and calphostin C. Moreover, stimulation of SW-480 cells by thrombin or PMA led to a significant increase in TF mRNA within 3 h as measured by the reversetranscription PCR method, which was also dependent on the activation of PKC. The unattered decay rate of thrombin-enhanced TF mRNA, evaluated after the addition of staurosporine, suggested that its inhibitory effect occurred at a transcription level. Our data suggest that thrombin enhances TF gene expression and protein synthesis in tumour cells in vitro via PKC activation. The induction of TF expression in tumour cells by thrombin indicates that tumour-associated PCA might have a positive-feedback effect on in vivo local propagation of thrombus by thrombin formation.

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Section: Discussionsupporting

confidence: 90%

Tissue factor activity of SW-480 human colon adenocarcinoma cells is modulated by thrombin and protein kinase C activation

Chiang

Yang²,

Lin³

et al. 1998

Br J Cancer

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“…All stimuli that are known to increase TF procoagulant activity on cell surfaces without increasing TF protein levels - i.e., freezing and thawing, sonication, nonionic detergents, proteases, phospholipases, apoptosis, complement, calcium ionophores, oxidizing agents and sulfhydryl reactive compounds - also increase invariably the exposure of PS on the outer cell surface [8;13;15–23]. A number of studies with relipidated TF protein have established that the presence of anionic phospholipids, such as phosphatidylserine (PS) in the phospholipid mixture greatly accelerates TF procoagulant activity [7–12].…”

Section: Tissue Factor Decryption: Role For Phosphatidylserinementioning

confidence: 99%

Tissue Factor encryption and decryption: Facts and controversies

Rao

Kothari

Pendurthi

2012

Thrombosis Research

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Tissue factor (TF)-initiated coagulation plays a critical role in both hemostatsis and thrombosis. It is generally believed that most of the tissue factor expressed on cell surfaces is maintained in a cryptic, i.e., coagulantly inactive state and an activation step (decryption) is required for the expression of maximum TF procoagulant activity. However, what exactly constitutes cryptic or procoagulant TF, molecular differences between these two forms and mechanisms that are responsible for transformation from one to the other form are not entirely clear and remain highly controversial, thus are a matter of ongoing debate. This brief review discusses pertinent literature on TF encryption/decryption with specific emphasis on the role of membrane phospholipids and reduction/oxidation of the TF Cys186–Cys209 disulfide bond in regulating TF activity at cell surfaces.

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“…Studies thereafter showed that the presence of anionic phospholipids, such as PS in the phospholipid mixture greatly accelerates TF procoagulant activity [12;26-30]. Almost all stimuli that are known to increase procoagulant activity of cryptic TF on cell surfaces, i.e., freezing and thawing, sonication, nonionic detergents, proteases, phospholipases, apoptosis, complement, calcium ionophores, oxidizing agents and sulfhydryl reactive compounds, also increase invariably the exposure of PS on the outer cell surface [5;8;12;22;31-37]. Although the coincidence of PS exposure and TF decryption does not necessarily prove that the increase in PS is solely responsible for TF decryption, the critical and proven role of PS in supporting TF procoagulant activity and the observation that blocking PS by annexin V reduces the procoagulant activity of decrypted TF in many cell types strongly implicate that PS plays a critical role in TF decryption.…”

Section: Models Of Tissue Factor Encryption/decryptionmentioning

confidence: 99%

Tissue factor: mechanisms of decryption

Kothari

Pendurthi³

2012

Front Biosci

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Tissue factor (TF) is a cellular receptor for clotting factor VII/VIIa (FVII/FVIIa). Formation of TF-FVIIa complexes on cell surfaces not only triggers the coagulation cascade but also transduces cell signaling via activation of protease-activated receptors. It is generally believed that only a small fraction of the TF found on cell surfaces is active in coagulation whereas the vast majority is cryptic (non-functional) in coagulation. It is unclear how cryptic TF differs from the coagulant active TF or potential mechanisms involved in transformation of cryptic TF to the coagulant active form. Both cryptic and coagulant active TF forms can bind FVIIa. It is generally believed that cryptic TF-FVIIa complexes fail to activate factor X as the protein substrate binding site is buried in the encrypted complex and a change in TF-FVIIa complex that exposes the substrate binding site leads to its decryption. Exposure of phosphatidylserine (PS) in response to various chemical or pathophysiological stimuli has been considered as the most potent inducer of TF decryption. In addition to PS, TF self-association and association with specialized membrane domains may also play a role in TF decryption. Recent studies suggest that cryptic form of TF contains unpaired cysteine thiols at Cys186 and Cys209 in the membrane-proximal domain, whereas the coagulant active form of TF is thought to have an oxidized Cys186-Cys209 disulfide bond. It has been suggested that protein disulfide isomerase (PDI) regulates TF decryption through its oxidoreductase activity by targeting this disulfide bond or regulating the PS equilibrium at the plasma membrane. However, this hypothesis requires further validation to become an accepted mechanism. In this article, we critically review literature on TF encryption/decryption with specific emphasis on recently published data and provide our perspective on this subject.

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Phospholipase C from Bacillus cereus and Its Use in Studies of Tissue Thromboplastin

Abstract: A simplified method for the purification of phospholipase C from Bacillus cereus is described.

Cited by 90 publications

References 17 publications

Tissue factor activity of SW-480 human colon adenocarcinoma cells is modulated by thrombin and protein kinase C activation

Tissue factor activity of SW-480 human colon adenocarcinoma cells is modulated by thrombin and protein kinase C activation

Tissue Factor encryption and decryption: Facts and controversies

Tissue factor: mechanisms of decryption

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