Ultrastructural localization of coagulation factor V in human platelets

Abstract The distribution and transport in platelets of human coagulation Factor V was investigated by immunofluorescent and immunoelectron microscopy. In resting intact platelets, little surface staining was observed by immunofluorescence. In permeable resting cells, punctate staining similar to that reported for fibrinogen (Fbg), thrombospondin (TSP), fibronectin (Fn), von Willebrand factor (VWF), B-thromboglobulin (BTG), and platelet Factor 4 (PF4) was observed. Double label immunofluorescent staining for Fbg and Factor V demonstrated colocalization, suggesting their presence in the same intracellular structure. Thrombin stimulation induced the appearance of larger (approximately 0.5 mu) immunofluorescent masses of these proteins which exactly colocalized. Thus, at the light level, Factor V and Fbg are localized in the same structure in resting and thrombin-stimulated cells. On the ultrastructural level, an alpha granule localization for Fbg has previously been established. We have extended our immunofluorescent observations regarding the localization of Factor V in human platelets by use of transmission electron microscopy of antibody-stained ultrathin frozen sections. In resting cells, staining of virtually all alpha granules was observed for Factor V. In contrast, consistent staining was absent from other organelles including plasma membranes, mitochondria, and vacuolar structures which may represent the open canalicular system. These data thus establish at the ultrastructural level an alpha granule localization of human coagulation Factor V.

Download Full-text

Ultrastructural localization of coagulation factor V in human platelets

Blood ◽

10.1182/blood.v68.1.244.bloodjournal681244 ◽

1986 ◽

Vol 68 (1) ◽

pp. 244-249 ◽

Cited By ~ 1

Author(s):

JD Wencel-Drake ◽

B Dahlback ◽

JG White ◽

MH Ginsberg

Keyword(s):

Plasma Membranes ◽

Coagulation Factor ◽

Ultrastructural Localization ◽

Ultrastructural Level ◽

Human Platelets ◽

Immunofluorescent Staining ◽

Resting Cells ◽

Factor V ◽

Platelet Factor ◽

Coagulation Factor V

The distribution and transport in platelets of human coagulation Factor V was investigated by immunofluorescent and immunoelectron microscopy. In resting intact platelets, little surface staining was observed by immunofluorescence. In permeable resting cells, punctate staining similar to that reported for fibrinogen (Fbg), thrombospondin (TSP), fibronectin (Fn), von Willebrand factor (VWF), B-thromboglobulin (BTG), and platelet Factor 4 (PF4) was observed. Double label immunofluorescent staining for Fbg and Factor V demonstrated colocalization, suggesting their presence in the same intracellular structure. Thrombin stimulation induced the appearance of larger (approximately 0.5 mu) immunofluorescent masses of these proteins which exactly colocalized. Thus, at the light level, Factor V and Fbg are localized in the same structure in resting and thrombin-stimulated cells. On the ultrastructural level, an alpha granule localization for Fbg has previously been established. We have extended our immunofluorescent observations regarding the localization of Factor V in human platelets by use of transmission electron microscopy of antibody-stained ultrathin frozen sections. In resting cells, staining of virtually all alpha granules was observed for Factor V. In contrast, consistent staining was absent from other organelles including plasma membranes, mitochondria, and vacuolar structures which may represent the open canalicular system. These data thus establish at the ultrastructural level an alpha granule localization of human coagulation Factor V.

Download Full-text

Identification of human megakaryocyte coagulation factor V

Blood ◽

10.1182/blood.v65.6.1396.1396 ◽

1985 ◽

Vol 65 (6) ◽

pp. 1396-1406 ◽

Cited By ~ 9

Author(s):

WL Nichols ◽

DA Gastineau ◽

LA Solberg ◽

KG Mann

Keyword(s):

Bone Marrow ◽

Human Factor ◽

Human Platelet ◽

Coagulation Factor ◽

Immunofluorescent Staining ◽

Factor V ◽

Igg Antibody ◽

Platelet Factor ◽

Glass Slides ◽

Coagulation Factor V

Abstract Specific monoclonal and polyclonal antibody reagents and a double antigen indirect immunofluorescence microscopy technique were used to visualize coagulation factor V in human bone marrow. Marrow aspirates were smeared directly on glass slides, or washed and cytospun onto glass slides, or processed and plated into a plasma/methylcellulose cell culture system. Morphologically identifiable colonies of megakaryocytes, erythrocytes, granulocytes, or monocytes/macrophages were removed from 14- to 18-day marrow culture dishes by micropipette and streaked onto glass slides. Smears of marrow cell preparations were air-dried, fixed, washed, and incubated sequentially with primary IgG antibody reagents and with secondary anti-IgG antibody reagents conjugated with either fluorescein or rhodamine. Preparations were examined and photographed through a microscope suitably equipped for two-color fluorescence and phase contrast analysis. Cells of megakaryocytic lineage were identified by their immunofluorescent reactivity with murine monoclonal antibody HP1–1D, specific for human platelet plasma membrane glycoprotein IIb/IIIa (GP IIb/IIIa), or by their immunofluorescent reactivity with monoclonal or polyclonal antibodies specific for von Willebrand factor (vWF) or for platelet factor 4 (PF4). Coagulation factor V in bone marrow was detected by simultaneous immunofluorescent staining with polyclonal burro anti- human factor V antibody or with a panel of murine monoclonal anti-human factor V antibodies. The double antigen immunofluorescence staining technique, incorporating appropriate controls, revealed that coagulation factor V was principally located in marrow cells simultaneously identified as megakaryocytes by antibodies to GP IIb/IIIa, vWF, or PF4. The specific immunofluorescence of factor V in megakaryocytes and platelets was eliminated when excess purified factor V antigen was preincubated with anti-factor V antibody. Our observations establish the presence of human megakaryocyte coagulation factor V, confirm the presence of human platelet factor V, and indicate that human megakaryocyte/platelet coagulation factor V is a lineage- associated protein.

Download Full-text

Identification of human megakaryocyte coagulation factor V

Blood ◽

10.1182/blood.v65.6.1396.bloodjournal6561396 ◽

1985 ◽

Vol 65 (6) ◽

pp. 1396-1406

Author(s):

WL Nichols ◽

DA Gastineau ◽

LA Solberg ◽

KG Mann

Keyword(s):

Bone Marrow ◽

Human Factor ◽

Human Platelet ◽

Coagulation Factor ◽

Immunofluorescent Staining ◽

Factor V ◽

Igg Antibody ◽

Platelet Factor ◽

Glass Slides ◽

Coagulation Factor V

Specific monoclonal and polyclonal antibody reagents and a double antigen indirect immunofluorescence microscopy technique were used to visualize coagulation factor V in human bone marrow. Marrow aspirates were smeared directly on glass slides, or washed and cytospun onto glass slides, or processed and plated into a plasma/methylcellulose cell culture system. Morphologically identifiable colonies of megakaryocytes, erythrocytes, granulocytes, or monocytes/macrophages were removed from 14- to 18-day marrow culture dishes by micropipette and streaked onto glass slides. Smears of marrow cell preparations were air-dried, fixed, washed, and incubated sequentially with primary IgG antibody reagents and with secondary anti-IgG antibody reagents conjugated with either fluorescein or rhodamine. Preparations were examined and photographed through a microscope suitably equipped for two-color fluorescence and phase contrast analysis. Cells of megakaryocytic lineage were identified by their immunofluorescent reactivity with murine monoclonal antibody HP1–1D, specific for human platelet plasma membrane glycoprotein IIb/IIIa (GP IIb/IIIa), or by their immunofluorescent reactivity with monoclonal or polyclonal antibodies specific for von Willebrand factor (vWF) or for platelet factor 4 (PF4). Coagulation factor V in bone marrow was detected by simultaneous immunofluorescent staining with polyclonal burro anti- human factor V antibody or with a panel of murine monoclonal anti-human factor V antibodies. The double antigen immunofluorescence staining technique, incorporating appropriate controls, revealed that coagulation factor V was principally located in marrow cells simultaneously identified as megakaryocytes by antibodies to GP IIb/IIIa, vWF, or PF4. The specific immunofluorescence of factor V in megakaryocytes and platelets was eliminated when excess purified factor V antigen was preincubated with anti-factor V antibody. Our observations establish the presence of human megakaryocyte coagulation factor V, confirm the presence of human platelet factor V, and indicate that human megakaryocyte/platelet coagulation factor V is a lineage- associated protein.

Download Full-text

Identification of Ten Novel Mutations Associated with Inherited Coagulation Factor V Deficiency.

Blood ◽

10.1182/blood.v104.11.1030.1030 ◽

2004 ◽

Vol 104 (11) ◽

pp. 1030-1030

Author(s):

Rinku Patel ◽

Jacky Cutler ◽

Campbell Tait ◽

Geoffrey Savidge

Keyword(s):

Missense Mutation ◽

Coagulation Factor ◽

Compound Heterozygous ◽

Factor V ◽

Single Chain ◽

Novel Mutations ◽

Platelet Factor ◽

Coagulation Factor V ◽

Factor V Gene ◽

V Gene

Abstract Factor V is a rare bleeding disorder characterized by low levels of plasma and/or platelet factor V, with an estimated prevalence of 1/1,000,000 and results from defects in the factor V gene. Human coagulation factor V (FV), a single chain glycoprotein, is synthesized in hepatocytes and megakaryocytes with 80% circulating free in plasma and the remainder being released upon platelet activation. The factor V gene comprises 25 exons ranging in size from 72bp to 2820bp coding for a protein which is oriented as A1-A2-B-A3-C1-C2 domains. FV is activated to its active form (FVa) by thrombin or activated factor X (FXa) which removes the B domain, generating a heavy chain and a light chain that are linked together in the presence of calcium ions. FVa binds to FXa and serves as its cofactor in the prothrombinase complex to convert prothrombin to thrombin. There is a high degree of homology between the A and C domains of FV and FVIII. We have investigated 8 unrelated patients from two centres with phenotypic and clinical charisteristics of FV deficiency. Mutation screening was carried out in these patients using Denaturing high performance liquid chromatography (dHPLC) and sequencing. Probable causative mutations were identified in all patients. A total of 10 novel mutations were identified in 8 patients and were located in the A1, A2, A3 and B domains. No mutations were identified in the C domain, and entries on the FV mutation database support our findings that mutations in this domain are less common than elsewhere in this gene. 5/8 patients were diagnosed with mild-moderate FV deficiency, and single heterozygous mutations were identified in each of these patients. 3 missense , 1 donor splicesite and 1 nonsense mutation were identified in the A1, A3 and B domains. The remaining 3/8 patients had severe FV deficiency (FV levels <2u/dl). One was compound heterozygous for 2 missense mutations in the A3 domain; one had a missense mutation in the A2 domain and a frameshift mutation (insertion of a single base pair) in the A3 domain. We have as yet identified only a heterozygous missense mutation in the third patient with severe FV deficiency. Phenotypic data and family history are strongly suggestive of the presence of a second mutation. Quantitative DNA analysis has confirmed the presence of 2 FV alleles, and RNA analysis is in progress to identify the second mutation. 100 normal alleles were analysed by dHPLC analysis or allele specific amplification to exclude these changes from being polymorphisms. We also have examined the homology between factor V and factor VIII, and the degree of similarity, between native and mutant amino acids to support these mutations as being causative of FV deficiency.

Download Full-text

Coagulation Factor V Leiden Mutation Was Detected in the Patients with Activated Protein C Resistance in Thailand

Thrombosis and Haemostasis ◽

10.1055/s-0037-1615201 ◽

1998 ◽

Vol 80 (08) ◽

pp. 344-345 ◽

Cited By ~ 2

Author(s):

Pasra Arnutti ◽

Motofumi Hiyoshi ◽

Wichai Prayoonwiwat ◽

Oytip Nathalang ◽

Chamaiporn Suwanasophon ◽

...

Keyword(s):

Protein C ◽

Activated Protein C ◽

Factor V Leiden ◽

Coagulation Factor ◽

Factor V ◽

Activated Protein C Resistance ◽

Factor V Leiden Mutation ◽

Coagulation Factor V

Download Full-text

Phenotyping and Genotyping of Coagulation Factor V Leiden

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650258 ◽

1996 ◽

Vol 75 (02) ◽

pp. 267-269 ◽

Cited By ~ 27

Author(s):

H Engel ◽

L Zwang ◽

H H D M van Vliet ◽

J J Michiles ◽

J Stibbe ◽

...

Keyword(s):

Factor V Leiden ◽

Coagulation Factor ◽

Diagnostic Value ◽

Resistance Test ◽

Amplification Refractory Mutation System ◽

Factor V ◽

Chain Reactions ◽

Apc Resistance ◽

Specificity And Sensitivity ◽

Coagulation Factor V

SummaryThe currently used activated Protein C resistance test demonstrated to be of limited diagnostic value for the detection of the mutant Factor V Leiden. Moreover, this assay is not useful for patients under anticoagulant therapy. A modification of the APC resistance test, applying Factor V deficient plasma is described which demonstrates a specificity and sensitivity of 1.0. The superiority of the modified APC resistance test over the existing APC resistance test was verified by genotyping.For that purpose, the Amplification Refractory Mutation System (ARMS) was applied to the detection of the G to A mutation at position 1691 in the gene encoding coagulation Factor V. The mutation at that position could be easily detected by using each of two allele-specific oligonucleotide primers concomitantly with one common primer in two separate polymerase chain reactions, thereby amplifying a fragment of 186 base-pairs of the Factor V gene.

Download Full-text