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Journal of Thrombosis and Haemostasis :... Jul 2017Factor V (FV) is a regulator of both pro- and anticoagulant pathways. It circulates as a single-chain procofactor, which is activated by thrombin or FXa to FVa that... (Review)
Review
Factor V (FV) is a regulator of both pro- and anticoagulant pathways. It circulates as a single-chain procofactor, which is activated by thrombin or FXa to FVa that serves as cofactor for FXa in prothrombin activation. The cofactor function of FVa is regulated by activated protein C (APC) and protein S. FV can also function as an anticoagulant APC cofactor in the inhibition of FVIIIa in the membrane-bound tenase complex (FIXa/FVIIIa). In recent years, it has become clear that FV also functions in multiple ways in the tissue factor pathway inhibitor (TFPI) anticoagulant pathway. Of particular importance is a FV splice variant (FV-Short) that serves as a carrier and cofactor to TFPIα in the inhibition of FXa. FV-Short is generated through alternative splicing of exon 13 that encodes the large activation B domain. A highly negatively charged binding site for TFPIα is exposed in the C-terminus of the FV-Short B domain, which binds the positively charged C-terminus of TFPIα, thus keeping TFPIα in circulation. The binding of TFPIα to FV-Short is also instrumental in localizing the inhibitor to the surface of negatively charged phospholipids, where TFPIα inhibits FXa in process that is stimulated by protein S. Plasma FV activation intermediates and partially proteolyzed platelet FV similarly bind TFPIα with high affinity and regulate formation of prothrombinase. The novel insights gained into the interaction between FV isoforms, TFPIα, and protein S have opened a new avenue for research about the mechanisms of coagulation regulation and also for future development of therapeutics aimed at modulating coagulation.
Topics: Alternative Splicing; Anticoagulants; Binding Sites; Blood Coagulation; Blood Coagulation Tests; Exons; Factor V; Factor VIIIa; Humans; Lipoproteins; Point Mutation; Protein Binding; Protein C; Protein Domains; Protein Isoforms; Protein S; Thrombin; Thrombophilia; Thromboplastin
PubMed: 28671348
DOI: 10.1111/jth.13665 -
The Journal of Biological Chemistry Mar 2011Protein S-palmitoylation, the reversible thioester linkage of a 16-carbon palmitate lipid to an intracellular cysteine residue, is rapidly emerging as a fundamental,... (Review)
Review
Protein S-palmitoylation, the reversible thioester linkage of a 16-carbon palmitate lipid to an intracellular cysteine residue, is rapidly emerging as a fundamental, dynamic, and widespread post-translational mechanism to control the properties and function of ligand- and voltage-gated ion channels. Palmitoylation controls multiple stages in the ion channel life cycle, from maturation to trafficking and regulation. An emerging concept is that palmitoylation is an important determinant of channel regulation by other signaling pathways. The elucidation of enzymes controlling palmitoylation and developments in proteomics tools now promise to revolutionize our understanding of this fundamental post-translational mechanism in regulating ion channel physiology.
Topics: Animals; Humans; Ion Channel Gating; Ion Channels; Lipoylation; Protein Modification, Translational; Protein S; Signal Transduction
PubMed: 21216969
DOI: 10.1074/jbc.R110.210005 -
Journal of Thrombosis and Haemostasis :... Jan 2022Factor V-Short (FV756-1458) is a natural splice variant in which 702 residues are deleted from the B domain. It exposes an acid region (AR2; 1493-1537) that binds tissue...
The preAR2 region (1458-1492) in factor V-Short is crucial for the synergistic TFPIα-cofactor activity with protein S and the assembly of a trimolecular factor Xa-inhibitory complex comprising FV-Short, protein S, and TFPIα.
BACKGROUND
Factor V-Short (FV756-1458) is a natural splice variant in which 702 residues are deleted from the B domain. It exposes an acid region (AR2; 1493-1537) that binds tissue factor pathway inhibitor alpha (TFPIα). Protein S also interacts with TFPIα and serves as TFPIα-cofactor in factor Xa (FXa) inhibition. FV-Short and protein S function as synergistic TFPIα-cofactors in inhibition of FXa. FV810-1492 is an artificial FV-Short variant that cannot synergize with protein S as TFPIα cofactor even though it contains AR2 and binds TFPIα.
OBJECTIVE
To elucidate the mechanisms for the synergism between FV756-1458 and protein S as TFPIα cofactors.
METHODS
Four FV-Short variants were created, FV756-1458 and FV712-1458 contained the preAR2 region (1458-1492), whereas FV810-1492 and FV713-1492 lacked this region. The synergistic TFPIα cofactor activity between FV-Short variants and protein S was analyzed by FXa-inhibition. A microtiter-based assay tested binding between FV-Short variants, protein S, and TFPIα.
RESULTS
The two preAR2-containing FV-Short variants were active as synergistic TFPIα cofactors, whereas the other two were inactive. All variants bound to TFPIα. None of the FV-Short variants bound directly to protein S. The combination of TFPIα and preAR2-containing FV-Short variants bound protein S, whereas TFPIα together with the preAR2-minus variants did not. Protein S potentiated TFPIα-binding to the preAR2-containing variants and binding between TFPIα and protein S was stimulated only by the preAR2-containing variants.
CONCLUSION
The preAR2 region is demonstrated to be crucial for the synergistic TFPIα-cofactor activity between FV-Short and protein S and for the assembly of a trimolecular FXa-inhibitory complex comprising FV-Short, protein S, and TFPIα.
Topics: Blood Coagulation; Factor V; Factor Xa; Humans; Lipoproteins; Protein S; Thrombin
PubMed: 34623729
DOI: 10.1111/jth.15547 -
Haematologica Apr 2008
Topics: Blood Coagulation; Blood Coagulation Factors; Enzyme Activation; Humans; Mutation; Protein C; Protein S; Protein S Deficiency; Recurrence; Thromboembolism; Thrombophilia
PubMed: 18379009
DOI: 10.3324/haematol.12691 -
The Plant Cell Jun 2023PHYTOCHROME KINASE SUBSTRATE (PKS) proteins are involved in light-modulated changes in growth orientation. They act downstream of phytochromes to control hypocotyl...
PHYTOCHROME KINASE SUBSTRATE (PKS) proteins are involved in light-modulated changes in growth orientation. They act downstream of phytochromes to control hypocotyl gravitropism in the light and act early in phototropin signaling. Despite their importance for plant development, little is known about their molecular mode of action, except that they belong to a protein complex comprising phototropins at the plasma membrane (PM). Identifying evolutionary conservation is one approach to revealing biologically important protein motifs. Here, we show that PKS sequences are restricted to seed plants and that these proteins share 6 motifs (A to F from the N to the C terminus). Motifs A and D are also present in BIG GRAIN, while the remaining 4 are specific to PKSs. We provide evidence that motif C is S-acylated on highly conserved cysteines, which mediates the association of PKS proteins with the PM. Motif C is also required for PKS4-mediated phototropism and light-regulated hypocotyl gravitropism. Finally, our data suggest that the mode of PKS4 association with the PM is important for its biological activity. Our work, therefore, identifies conserved cysteines contributing to PM association of PKS proteins and strongly suggests that this is their site of action to modulate environmentally regulated organ positioning.
Topics: Phytochrome; Arabidopsis Proteins; Arabidopsis; Protein S; Light; Phototropism; Hypocotyl; Acylation
PubMed: 36972404
DOI: 10.1093/plcell/koad096 -
Biomolecules Mar 2022Covalent binding between nitric oxide (NO) and a protein's free thiol group (SH) is termed protein S-nitrosylation. Protein S-nitrosylation is involved in cellular...
Covalent binding between nitric oxide (NO) and a protein's free thiol group (SH) is termed protein S-nitrosylation. Protein S-nitrosylation is involved in cellular regulation mechanisms that underlie a wide range of critical functions, such as apoptosis, alteration of enzyme activities, and transcription-factor stability. Impaired protein S-nitrosylation is associated with a growing list of pathophysiological conditions, such as cardiovascular disease, multiple sclerosis, pulmonary hypertension, and sickle cell disease. The enzyme paraoxonase 1 (PON1) binds to high-density lipoprotein to provide many of its antiatherogenic properties. The enzyme has a strong antioxidant capacity, which protects fats, lipids, and lipoproteins from oxidation, in addition to breaking down oxidized fats. We investigated the effect of S-S transnitrosylation on PON1 activities. Incubation of recombinant PON1 (rePON1) with nitrosylated human serum albumin (HSA-NO) resulted in S-nitrosylation of about 70% of the rePON1, as measured by Q-TOF LC/MS. S-nitrosylation significantly increased rePON1 hydrolytic activities. It also increased rePON1's ability to inhibit low-density lipoprotein oxidation induced by Cu. Finally, it increased the enzyme's penetration into macrophage cells by 31%. Our findings suggest that S-nitrosylation of rePON1 improves its biological functions which may positively affect atherosclerosis disease progression.
Topics: Antioxidants; Aryldialkylphosphatase; Humans; Lipoproteins, HDL; Lipoproteins, LDL; Protein S
PubMed: 35327606
DOI: 10.3390/biom12030414 -
Oral Diseases Nov 2017All living tissues require essential nutrients such as amino acids, fatty acids, carbohydrates, minerals, vitamins, and water. The skeleton requires nutrients for... (Review)
Review
All living tissues require essential nutrients such as amino acids, fatty acids, carbohydrates, minerals, vitamins, and water. The skeleton requires nutrients for development, maintaining bone mass and density. If the skeletal nutritional requirements are not met, the consequences can be quite severe. In recent years, there has been growing interest in promotion of bone health and inhibition of vascular calcification by vitamin K2. This vitamin regulates bone remodeling, an important process necessary to maintain adult bone. Bone remodeling involves removal of old or damaged bone by osteoclasts and its replacement by new bone formed by osteoblasts. The remodeling process is tightly regulated, when the balance between bone resorption and bone formation shifts to a net bone loss results in the development of osteoporosis in both men and women. In this review, we focus on our current understanding of the effects of vitamin K2 on bone cells and its role in prevention and treatment of osteoporosis.
Topics: Animals; Bone Development; Bone Remodeling; Bone and Bones; Calcium-Binding Proteins; Extracellular Matrix Proteins; Humans; Osteoblasts; Osteocalcin; Osteoclasts; Osteocytes; Protein S; Vitamin K 2; Matrix Gla Protein
PubMed: 27976475
DOI: 10.1111/odi.12624 -
Open Biology Apr 2022Protein S-acylation, more commonly known as protein palmitoylation, is a biological process defined by the covalent attachment of long chain fatty acids onto cysteine... (Review)
Review
Protein S-acylation, more commonly known as protein palmitoylation, is a biological process defined by the covalent attachment of long chain fatty acids onto cysteine residues of a protein, effectively altering the local hydrophobicity and influencing its stability, localization and overall function. Observed ubiquitously in all eukaryotes, this post translational modification is mediated by the 23-member family of zDHHC protein acyltransferases in mammals. There are thousands of proteins that are S-acylated and multiple zDHHC enzymes can potentially act on a single substrate. Since its discovery, numerous methods have been developed for the identification of zDHHC substrates and the individual members of the family that catalyse their acylation. Despite these recent advances in assay development, there is a persistent gap in knowledge relating to zDHHC substrate specificity and recognition, that can only be thoroughly addressed through reconstitution. Herein, we will review the various methods currently available for reconstitution of protein S-acylation for the purposes of identifying enzyme-substrate pairs with a particular emphasis on the advantages and disadvantages of each approach.
Topics: Acetyltransferases; Acylation; Animals; Mammals; Protein Processing, Post-Translational; Protein S; Substrate Specificity
PubMed: 35414257
DOI: 10.1098/rsob.210390 -
British Journal of Haematology Jul 1998Difficulties in the laboratory measurement of protein C and protein S levels cause problems in the diagnosis of deficiency states in individual patients and may...
Difficulties in the laboratory measurement of protein C and protein S levels cause problems in the diagnosis of deficiency states in individual patients and may complicate estimation of the prevalence of these states in the general population. Some difficulties may be due to unappreciated influences affecting the measured levels of proteins C and S. We measured protein C activity and antigen, total and free protein S antigen, and serum total cholesterol, high-density cholesterol and triglyceride in a community-based study of 150 adults (73 male, 77 female), age range 23-80 years. Participants were identified from the list of a single general practice by stratified random sampling within sex and decade of age. Protein C activity and antigen were strongly associated with serum lipids, mean levels increasing by approximately 0.25 u/ml as total cholesterol and triglyceride concentration each rose from the 5th to 95th centile. Total protein S antigen concentration was associated with total cholesterol, the mean rising by over 0.1 u/ml as total cholesterol increased from the 5th to the 95th centile, whilst a similar rise in triglyceride was associated with an increase in mean free protein S of more than 0.3 u/ml. Overall, physiological variation in total cholesterol and triglyceride concentration was associated with significant variation in protein C and protein S levels, independent of age and sex, suggesting that it is important to take serum lipids into account when investigating patients for protein C or protein S deficiency. Failure to do so may be misleading in some circumstances.
Topics: Adult; Age Distribution; Aged; Aged, 80 and over; Antigens; Cholesterol; Female; Humans; Male; Middle Aged; Protein C; Protein S; Sex Distribution; Triglycerides
PubMed: 9695981
DOI: 10.1046/j.1365-2141.1998.00800.x -
Journal of Thrombosis and Haemostasis :... Jul 2009Protein S is an anticoagulant cofactor of full-length tissue factor pathway inhibitor (TFPI) that facilitates optimal factor Xa-inhibition and efficient down-regulation... (Review)
Review
Protein S is an anticoagulant cofactor of full-length tissue factor pathway inhibitor (TFPI) that facilitates optimal factor Xa-inhibition and efficient down-regulation of thrombin generation in plasma. Protein S and TFPI are constitutively active in plasma and therefore provide an effective anticoagulant barrier against unwanted procoagulant activity in the circulation. In this review, we describe the current status on how TFPI-activity depends on protein S, and show that TFPI and protein S are major regulators of thrombin generation both in the absence and presence of activated protein C (APC). As there is covariation of plasma TFPI and protein S levels both in health and in disease, these findings suggest that the risk of venous thrombosis associated with protein S deficiency states might be in part explained by the accompanying low plasma TFPI levels.
Topics: Humans; Lipoproteins; Protein S; Thrombin; Venous Thrombosis
PubMed: 19630792
DOI: 10.1111/j.1538-7836.2009.03363.x