Distribution and relative levels of expression of the phosphoinositidase-C-linked G-proteins Gqα and G11α: Absence of G11α in human platelets and haemopoietically derived cell lines

1993 ◽  
Vol 1179 (2) ◽  
pp. 208-212 ◽  
Author(s):  
Graeme Milligan ◽  
Ian Mullaney ◽  
J.Fraser McCallum
Keyword(s):  
G Proteins ◽  
Cell Lines ◽  
Human Platelets

Presence of P2X1 Purinoceptors in Human Platelets and Megakaryoblastic Cell Lines

1997 ◽  
Vol 78 (06) ◽  
pp. 1500-1504 ◽  
Author(s):  
Catherine Vial ◽  
Béatrice Hechier ◽  
Catherine Léon ◽  
Jean-Pierre Cazenave ◽  
Christian Gachet
Keyword(s):  
Intracellular Calcium ◽  
G Proteins ◽  
Cell Lines ◽  
Calcium Influx ◽  
Human Platelets ◽  
P2y1 Receptor ◽  
Calcium Response ◽  
Ionotropic Receptors ◽  
External Calcium

SummaryHuman platelets are thought to possess at least two subtypes of purinoceptor, one of which, coupled to G-proteins, could be the P2Y1 receptor (Léon et al. 1997). However, it has been suggested that the unique rapid calcium influx induced by ADP in platelets could involve P2X1 ionotropic receptors (MacKenzie et al. 1996) and the aim of this study was thus to investigate the presence of P2X purinoceptors in platelets and megakaryoblastic cells. Using PCR experiments, we found P2X1 mRNA to be present in human platelets and megakaryoblastic cell lines. In platelets, the selective P2X1 agonist αβMeATP induced a rise in intracellular calcium only in the presence of external calcium and this effect was antagonized by suramin and PPADS. Repeated addition of a�MeATP desensitized the P2X1 purinoceptor but only slightly affected the ADP response, while no calcium response to αβMeATP was observed in megakaryoblastic cells. These results support the existence of functional P2X1 purinoceptors on human platelets and the presence of P2X1 transcripts in megakaryoblastic cell lines.

Interaction of Human Tumor Cells with Human Platelets and the Coagulation System

1983 ◽  
Vol 50 (03) ◽  
pp. 726-730 ◽  
Author(s):  
Hamid Al-Mondhiry ◽  
Virginia McGarvey ◽  
Kim Leitzel
Keyword(s):  
Tumor Cell ◽  
Tumor Cells ◽  
Cell Lines ◽  
Human Tumor ◽  
Human Platelets ◽  
Factor Vii ◽  
Coagulation System ◽  
Breast Adenocarcinoma ◽  
Activate Factor ◽  
Tumor Cell Lines

SummaryThis paper reports studies on the interaction between human platelets, the plasma coagulation system, and two human tumor cell lines grown in tissue culture: Melanoma and breast adenocarcinoma. The interaction was monitored through the use of 125I- labelled fibrinogen, which measures both thrombin activity generated by cell-plasma interaction and fibrin/fibrinogen binding to platelets and tumor cells. Each tumor cell line activates both the platelets and the coagulation system simultaneously resulting in the generation of thrombin or thrombin-like activity. The melanoma cells activate the coagulation system through “the extrinsic pathway” with a tissue factor-like effect on factor VII, but the breast tumor seems to activate factor X directly. Both tumor cell lines activate platelets to “make available” a platelet- derived procoagulant material necessary for the conversion of prothrombin to thrombin. The tumor-derived procoagulant activity and the platelet aggregating potential of cells do not seem to be inter-related, and they are not specific to malignant cells.

scholarly journals Chimeric Measles Virus (MV/RSV), Having Ectodomains of Respiratory Syncytial Virus (RSV) F and G Proteins Instead of Measles Envelope Proteins, Induced Protective Antibodies against RSV

Vaccines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 156
Author(s):  
Akihito Sawada ◽  
Takashi Ito ◽  
Yoshiaki Yamaji ◽  
Tetsuo Nakayama
Keyword(s):  
Respiratory Syncytial Virus ◽  
G Proteins ◽  
Cell Lines ◽  
Measles Virus ◽  
Pathological Finding ◽  
Control Group ◽  
Protein Coding ◽  
Virus Growth ◽  
Protective Antibodies ◽  
Syncytial Virus

In our previous study, fusion (F) or glyco (G) protein coding sequence of respiratory syncytial virus (RSV) was inserted at the P/M junction of the measles AIK-C vector (MVAIK), and the recombinant measles virus induced protective immune responses. In the present study, the ectodomains of measles fusion (F) and hemagglutinin (HA) proteins were replaced with those of RSV F and G proteins, and a chimeric MV/RSV vaccine was developed. It expressed F and G proteins of RSV and induced cytopathic effect (CPE) in epithelial cell lines (Vero, A549, and HEp-2 cells), but not in lymphoid cell lines (B95a, Jurkat, and U937 cells). A chimeric MV/RSV grew similarly to AIK-C with no virus growth at 39 °C. It induced NT antibodies against RSV in cotton rats three weeks after immunization through intramuscular route and enhanced response was observed after the second dose at eight weeks. After the RSV challenge with 106 PFU, significantly lower virus (101.4±0.1 PFU of RSV) was recovered from lung tissue in the chimeric MV/RSV vaccine group than in the MVAIK control group with 104.6±0.2 PFU (p < 0.001) and no obvious inflammatory pathological finding was noted. The strategy of ectodomain replacement in the measles virus vector is expected to lead to the development of safe and effective vaccines for other enveloped viruses.

scholarly journals Identification of Gz alpha as a pertussis toxin-insensitive G protein in human platelets and megakaryocytes

Blood ◽  
1991 ◽  
Vol 78 (5) ◽  
pp. 1247-1253 ◽  
Author(s):  
AW Gagnon ◽  
DR Manning ◽  
L Catani ◽  
A Gewirtz ◽  
M Poncz ◽  
...  
Keyword(s):  
G Protein ◽  
Cell Lines ◽  
Complete Sequence ◽  
Human Platelets ◽  
Northern Blotting ◽  
Nucleotide Sequencing ◽  
Major Band ◽  
Surface Receptors ◽  
G Protein Alpha Subunit ◽  
A Minor

Abstract G proteins mediate the interaction between cell surface receptors and intracellular effectors. Recent studies have shown that human retina and rat brain contain mRNA encoding a novel 40-Kd G protein alpha subunit referred to as Gz alpha. Studies with an antiserum selective for the predicted sequence of this protein have suggested that a similar protein is present in human platelets and is phosphorylated during platelet activation. To better understand the structure and function of this protein, the present studies examine its sequence in platelets and compare its abundance in human platelets, megakaryocytes, and two megakaryoblastic cell lines, HEL cells and Dami cells. Three different Gz alpha-selective antisera reacted with a 40-Kd protein in platelet membranes. None of these detected a corresponding protein in HEL or Dami cells, despite the presence in both cell lines of proteins recognized by antisera selective for three members of the Gi alpha family. Northern blotting with a Gz alpha-specific probe prepared from retinal Gz alpha showed two hybridizing species in platelet RNA: a major band at 3.5 kb and a minor band at 2.2 kb. Both were detectable in HEL and Dami cells, but at greatly reduced levels compared with platelets. RNA encoding Gz alpha was also detected in individual human megakaryocytes by in situ hybridization. The amount present approached that of Gi alpha 2′ the most abundant of the Gi alpha species present in platelets. The complete sequence of the platelet homolog to Gz alpha was determined from platelet RNA amplified by the polymerase chain reaction. The encoded protein was the same as those obtained in brain and retina. Thus, based on immunoreactivity and nucleotide sequencing, platelets and megakaryocytes contain substantial quantities of a protein identical to brain and retinal Gz alpha. The paucity of Gz alpha protein and RNA in the megakaryoblastic cell lines suggests that either there has been a selective loss of the ability to synthesize Gz alpha from these cells or that Gz alpha appears at a later stage in megakaryocyte development than does Gi alpha.

Stimulation by G Protein βγ Subunits of Phospholipase C β Isoforms in Human Platelets

1998 ◽  
Vol 79 (05) ◽  
pp. 1008-1013 ◽  
Author(s):  
Yoshiko Banno ◽  
Tomiko Asano ◽  
Yoshinori Nozawa
Keyword(s):  
Phospholipase C ◽  
G Protein ◽  
G Proteins ◽  
Human Platelet ◽  
Minor Component ◽  
Similar Efficacy ◽  
Human Platelets ◽  
Bovine Brain ◽  
Γ Subunit ◽  
A Minor

SummaryDifferent phospholipase C (PLC) isoforms were located in human platelet cytosol and membranes. PLCγ2 and PLCβ3b were mainly located in the cytosol and PLCβ2 and PLCβ3a were in both cytosol and membranes by using specific antibodies against PLC isozymes (Banno Y, Nakashima S, Ohzawa M, Nozawa Y. J Biol Chem 1996; 271: 14989-94). Three PLC fractions activated by G protein βγ subunits were purified from human platelet cytosol and membrane fractions. Two PLC fractions from membranes were identified as PLCβ2 and PLCβ3a, and one from cytosol was PLCβ3b. These PLCβ isoforms were activated by the purified βγ subunits of brain G proteins in the order PLCβ3b > PLCβ3a > PLCβ2. Western blot analysis of γ subunits of the purified platelet G proteins with antibodies against various standard γ subunits revealed that the major component of the γ subunit of Gi2 and Gq was γ5, and that γ7 was a minor component. Studies using various subtypes of βγ subunits, βγ2, βγ3, and βγ7 purified from bovine brain, βγ5 from bovine lung, or βγ12 from bovine spleen, failed to show differences in their ability to stimulate the isolated platelet PLCβ isoforms. These results suggest that the βγ subunits of Gi2 and Gq have similar efficacy in regulation of effectors in human platelets.

scholarly journals Signal transduction and glycophosphatidylinositol-linked proteins (lyn, lck, CD4, CD45, G proteins, and CD55) selectively localize in Triton- insoluble plasma membrane domains of human leukemic cell lines and normal granulocytes

Blood ◽  
1996 ◽  
Vol 87 (9) ◽  
pp. 3783-3794 ◽  
Author(s):  
I Parolini ◽  
M Sargiacomo ◽  
MP Lisanti ◽  
C Peschle
Keyword(s):  
Signal Transduction ◽  
G Proteins ◽  
Cell Lines ◽  
Tyrosine Kinases ◽  
Leukemic Cell ◽  
Receptor Activation ◽  
Leukemic Cells ◽  
Human Leukemic Cell ◽  
Leukemic Cell Lines ◽  
B Lymphoid

Src-family nonreceptor protein tyrosine kinases (NRPTK) are associated with cell surface receptors in large detergent-resistant complexes: in epithelial cells, yes is selectively located in vesicle structures containing caveolin (“caveolae”). These formations are typically also endowed with glycophosphatidylinositol (GPI)-anchored proteins. In the present study, we observed lck, lyn, src, hck, CD4, CD45, G proteins, and CD55 (decay-accelerating factor) expression in the buoyant low- density Triton-insoluble (LDTI) fraction of selected leukemic cell lines and granulocytes. We provide a detailed analysis of the two most highly expressed NRPTK, p53/p56lyn and p56lck, which are involved in the transduction of signals for proliferation and differentiation of monocytes/B lymphocytes and T lymphocytes, respectively. We show that lyn is selectively recovered in LDTI complexes isolated from human leukemic cell lines (promyelocytic [HL-60], erythroid [K562] and B- lymphoid [697]) and from normal human granulocytes, and that lck is recovered from LDTI fractions of leukemic T- and B-lymphoid cell lines (CEM, 697). In LDTI fractions of leukemic cells, lck and lyn are enriched 100-fold as compared with the total cell lysates. Analysis of these fractions by electron microscopy shows the presence of 70- to 200- nm vesicles: lyn and lck are homogenously distributed in the vesicles, as revealed by an immunogold labeling procedure. These novel results propose a role for these vesicles in signal transduction mechanisms of normal and neoplastic hematopoietic cells. In support of this hypothesis, we further observed that molecules participating in B- and T-cell receptor activation cofractionate in the LDTI fractions, CD45/lyn (B cells) and CD45/lck/CD4 (T cells).

Subcellular Localization of α-Subunits of Trimeric G-Proteins in Human Platelets

1997 ◽  
Vol 234 (2) ◽  
pp. 439-444 ◽  
Author(s):  
Aukje N. Giesberts ◽  
Mireille van Ginneken ◽  
Gertie Gorter ◽  
Eduardo G. Lapetina ◽  
Jan-Willem N. Akkerman ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
G Proteins ◽  
Human Platelets ◽  
Α Subunits

scholarly journals Small G Proteins Dexras1 and RHES and Their Role in Pathophysiological Processes

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ashish Thapliyal ◽  
Rashmi Verma ◽  
Navin Kumar
Keyword(s):  
Ion Channels ◽  
Cell Growth ◽  
G Proteins ◽  
Cell Lines ◽  
Calcium Ion ◽  
Small Gtpase ◽  
Calcium Ion Channels ◽  
Hormonal Release ◽  
Small G Proteins

Dexras1 and RHES, monomeric G proteins, are members of small GTPase family that are involved in modulation of pathophysiological processes. Dexras1 and RHES levels are modulated by hormones and Dexras1 expression undergoes circadian fluctuations. Both these GTPases are capable of modulating calcium ion channels which in turn can potentially modulate neurosecretion/hormonal release. These two GTPases have been reported to prevent the aberrant cell growth and induce apoptosis in cell lines. Present review focuses on role of these two monomeric GTPases and summarizes their role in pathophysiological processes.

scholarly journals Differential effects of G-protein activators on 5-hydroxytryptamine and platelet-derived growth factor release from streptolysin-O-permeabilized human platelets

1996 ◽  
Vol 314 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Philip J. PADFIELD ◽  
Ninder PANESAR ◽  
Patricia HENDERSON ◽  
Joseph J. BALDASSARE
Keyword(s):  
Growth Factor ◽  
G Protein ◽  
G Proteins ◽  
Protein S ◽  
Human Platelets ◽  
Dense Core ◽  
Platelet Derived Growth Factor ◽  
Permeabilized Cells ◽  
Streptolysin O ◽  
Dense Core Granules

In this paper we have used streptolysin O (SLO)-permeabilized human platelets to examine the G-protein(s) that control Ca2+-independent secretion from α and dense-core granules. As shown for electropermeabilized platelets, Ca2+ alone stimulated a concentration-dependent increase in 5-hydroxytryptamine (5-HT) (dense-core-granule marker) and platelet-derived growth factor (PDGF) (α-granule marker) release from the SLO-permeabilized cells. The EC50 values for Ca2+-dependent 5-HT and PDGF release were 5 μM and 10 μM respectively. Guanosine 5´-[γ-thio]triphosphate (GTP[S]) (100 μM) stimulated Ca2+-independent release from both α and dense-core granules. In contrast, AlF4- had no effect on Ca2+-independent release from either α or dense-core granules. Neither GTP[S] nor AlF4- appeared to have a significant effect on Ca2+-dependent release from α and dense-core granules. GTP[S] can activate both heterotrimeric and low-molecular-mass G-proteins, whereas AlF4- activates only heterotrimeric G-proteins. Our results, therefore suggest that secretion in the human platelet is regulated by a small G-protein. Both GTP[S]- and Ca2+-dependent secretion were effected by extending the time between permeabilization with SLO and stimulation of secretion. GTP[S]-stimulated secretion from α and dense-core granules decreased rapidly after permeabilization. In contrast, Ca2+-dependent 5-HT and PDGF release ran down at a much lower rate. These observations indicate that GTP[S] and Ca2+ act through parallel pathways to stimulate secretion from SLO-permeabilized platelets.

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