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  1. 6 Acta Biochimica Polonica

  2. 6 Archivum Immunologiae et Therapiae Experimentalis

  3. 4 Acta Protozoologica

  4. 4 Cellular and Molecular Biology Letters

  5. 1 Bulletin of the Veterinary Institute in Puławy

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  1. 2 Ciarkowski J.

  2. 2 Kuruvilla H.

  3. 2 Slusarz R.

  4. 1 Bartholomew J.

  5. 1 Bialkowska K.

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  1. 1 2013

  2. 1 2010

  3. 2 2009

  4. 1 2008

  5. 1 2005

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1

Crosstalk between G protein-coupled receptors and tyrosine kinase signalling; Src take centre stage

100%
Ptasznik A., Gewirtz A. M.
Archivum Immunologiae et Therapiae Experimentalis
|
2000
|
tom 48
|
nr 1
2

Interaction of class A G protein-coupled receptors with G proteins

88%
Slusarz R., Ciarkowski J.
Acta Biochimica Polonica
|
2004
|
tom 51
|
nr 1
A model for interaction of class A G protein-coupled receptor with the G protein Ga subunit is proposed using the rhodopsin-transducin (RD/Gt) prototype. The model combines the resolved interactions/distances, essential in the active RD*/Gt system, with the structure of Gta C-terminal peptide bound to RD* while stabilizing it. As­suming the interactions involve conserved parts of the partners, the model specifies the conserved Helix 2 non-polar X- - -X, Helix 3 DRY and Helix 7/8 NP- -Y- - F RD* mo­tifs interacting with the Gta C-terminal peptide, in compliance with the structure of the latter. A concomitant role of Gta and Gtγ C-termini in stabilizing RD* could po­ssibly be resolved assuming a receptor dimer as requisite for G protein activation.
3

Regulator of G-protein signalling expression and function in ovarian cancer cell lines

75%
Hurst J. H., Mendpara N., Hooks S. B.
Cellular and Molecular Biology Letters
|
2009
|
tom 14
|
nr 1
153-174
Regulator of G-protein signalling (RGS)2 proteins critically regulate signalling cascades initiated by G-protein coupled receptors (GPCRs) by accelerating the deactivation of heterotrimeric G-proteins. Lysophosphatidic acid (LPA) is the predominant growth factor that drives the progression of ovarian cancer by activating specific GPCRs and G-proteins expressed in ovarian cancer cells. We have recently reported that RGS proteins endogenously expressed in SKOV-3 ovarian cancer cells dramatically attenuate LPA stimulated cell signalling. The goal of this study was twofold: first, to identify candidate RGS proteins expressed in SKOV-3 cells that may account for the reported negative regulation of G-protein signalling, and second, to determine if these RGS protein transcripts are differentially expressed among commonly utilized ovarian cancer cell lines and non-cancerous ovarian cell lines. Reverse transcriptase-PCR was performed to determine transcript expression of 22 major RGS subtypes in RNA isolated from SKOV-3, OVCAR-3 and Caov-3 ovarian cancer cell lines and non-cancerous immortalized ovarian surface epithelial (IOSE) cells. Fifteen RGS transcripts were detected in SKOV-3 cell lines. To compare the relative expression levels in these cell lines, quantitative real time RT-PCR was performed on select transcripts. RGS19/GAIP was expressed at similar levels in all four cell lines, while RGS2 transcript was detected at levels slightly lower in ovarian cancer cells as compared to IOSE cells. RGS4 and RGS6 transcripts were expressed at dramatically different levels in ovarian cancer cell lines as compared to IOSE cells. RGS4 transcript was detected in IOSE at levels several thousand fold higher than its expression level in ovarian cancer cells lines, while RGS6 transcript was expressed fivefold higher in SKOV-3 cells as compared to IOSE cells, and over a thousand fold higher in OVCAR-3 and Caov-3 cells as compared to IOSE cells. Functional studies of RGS 2, 6, and 19/GAIP were performed by measuring their effects on LPA stimulated production of inositol phosphates. In COS-7 cells expressing individual exogenous LPA receptors, RGS2 and RSG19/GAIP attenuated signalling initiated by LPA1, LPA2, or LPA3, while RGS6 only inhibited signalling initiated by LPA2 receptors. In SKOV-3 ovarian cancer cells, RGS2 but not RGS6 or RGS19/GAIP, inhibited LPA stimulated inositol phosphate production. In contrast, in CAOV-3 cells RGS19/GAIP strongly attenuated LPA signalling. Thus, multiple RGS proteins are expressed at significantly different levels in cells derived from cancerous and normal ovarian cells and at least two candidate RGS transcripts have been identified to account for the reported regulation of LPA signalling pathways in ovarian cancer cells.
4

On the role of integrin-induced signalling in Rac activation; involrement of cytoskeletal and signalling molecules

75%
Bialkowska K., Fox J. E. B.
Cellular and Molecular Biology Letters
|
2002
|
tom 07
|
nr Suppl.
5
Content available remote

The role of G protein B subunits in the release of ATP from human erythrocytes

75%
Sprague R. S., Bowles E. A., Olearczyk J. J., Stephenson A. H., Lonigro A. J.
Journal of Physiology and Pharmacology
|
2002
|
tom 53
|
nr 4,1
Previously, we demonstrated that adenosine triphosphate (ATP) is released from human erythrocytes in response to mechanical deformation and that this release requires activation of a signal-transduction pathway involving adenylyl cyclase and the heterotrimeric G protein, Gs. Here we investigate the role of heterotrimeric G proteins of the Gi subtype in the release of ATP from human erythrocytes. In addition, we determined the profile of heterotrimeric G protein ß submits present in these erythrocyte membranes. The activity of Gi was stimulated by incubation of erythrocytes (20% hematocrit) with mastoparin (10 µM). ATP release was measured using the luciferin/luciferase assay. Heterotrimeric G protein ß subunits present in erythrocyte membranes were resolved using gel electrophoresis and subunit specific antibodies. Incubation of human erythrocytes with mastoparan (an activator ofGi/o) resulted in a 4.1 ±0.6-fold increase in ATP present in the medium (P<0.01). Human erythrocyte membranes stain positively for ß subunit types 1, 2, 3 and 4, all of which been reported to activate of some isoforms of adenylyl cyclase. Activation of the heterotrimeric G protein, Gi, results in ATP release from erythrocytes. This effect is may be related to the activity of ß submits associated with this G protein in the human erythrocyte.
6

Expression in Escherichia coli of human ARHGAP6 gene and purification of His-tagged recombinant protein

75%
Ochocka A. M., Czyzewska M., Pawelczyk T.
Acta Biochimica Polonica
|
2003
|
tom 50
|
nr 1
In this report we describe cloning and expression of human Rho GTPase activating protein (ARHGAP6) isoform 4 in Escherichia coli cells as a fusion protein with 6xHis. We cloned the ARHGAP6 cDNA into the bacterial expression vector pPROEX-1. In­duction of the 6xHis-ARHGAP6 protein in BL21(DE3) and DH5a cells caused lysis of the cells irrespective of the kind of culture medium used. Successful expression of the fusion protein was obtained in the MC4100Δibp mutant strain lacking the small heat-shock proteins IbpA and IbpB. Reasonable yield was obtained when the cells were cultured in Terrific Broth + 1% glucose medium at 22°C for 16 h. The optimal cell density for expression of soluble 6xHis-ARHGAP6 protein was at A600 about 0.5. Un­der these conditions over 90% of the fusion protein was present in a soluble form. The 6xHis-ARHGAP6 protein was purified to near homogeneity by a two step procedure comprising chromatography on Ni-nitrilotriacetate and cation exchange columns. The expression system and purification procedure employed made it possible to obtain 1-2 mg of pure 6xHis-ARHGAP6 protein from 300 ml (1.5 g of cells) of E. coli culture.
7

A burgeoning family of biological mediators: chemokines and chemokine receptors

75%
Le Y., Gong W., Shen W., Li B., Dunlop N. M., Wang J. M.
Archivum Immunologiae et Therapiae Experimentalis
|
2000
|
tom 48
|
nr 3
8

Emerging role of alternative splicing of CRF1 receptor in CRF signaling

63%
Zmijewski M. A., Slominski A. T.
Acta Biochimica Polonica
|
2010
|
tom 57
|
nr 1
1-13
Alternative splicing of mRNA is one of the most important mechanisms responsible for an increase of the genomic capacity. Thus the majority of human proteins including G protein-coupled receptors (GPCRs) possess several isoforms as a result of mRNA splicing. The corticotropin-releasing factor (CRF) and its receptors are the most proximal elements of hypothalamic-pituitary-adrenal axis (HPA) - the central machinery of stress response. Moreover, expression of CRF and regulated activity of CRF receptor type 1 (CRF1) can also play an important role in regulation of local stress response in peripheral tissues including skin, gastrointestinal tract or reproductive system. In humans, expression of at least eight variants of CRF1 mRNA (α, β, c, d, e, f, g and h) was detected and alternative splicing was found to be regulated by diverse physiological and pathological factors including: growth conditions, onset of labor, during pregnancy or exposure to ultraviolet irradiation. The pattern of expression of CRF1 isoforms is cell type specific and recently has been linked to observed differences in responsiveness to CRF stimulation. In the proposed model of regulation of CRF-signaling, isoform CRF1α plays a central role. Other isoforms modulate its activity by oligomerization, leading to alteration in receptor trafficking, localization and function. Co-expression of CRF1 isoforms modulates sensitivity of cells to the ligands and influences downstream coupling to G-proteins. The other possible regulatory mechanisms include fast mRNA and/or protein turnover or decoy receptor function of CRF1 isoforms. Taken together, alternative splicing of CRF1 can represent another level of regulation of CRF-mediated stress responses at the central and peripheral levels. Chronic stress or malfunction of the HPA-axis have been linked to numerous human pathologies, suggesting that alternative splicing of CRF1 receptor could represent a promising target for drugs development.
9

The regulating function of heterotrimeric G proteins in the immune system

63%
Wang Y., Li Y., Shi G.
Archivum Immunologiae et Therapiae Experimentalis
|
2013
|
tom 61
|
nr 4
10

Ras pathway activation in gliomas: a strategic target for intranasal administration of perillyl alcohol

63%
Orlando da Fonseca C., Linden R., Futuro D., Gattass C. R., Quirico-Santos T.
Archivum Immunologiae et Therapiae Experimentalis
|
2008
|
tom 56
|
nr 4
11

Role of RGS proteins in regulating the migration of B lymphocytes

63%
Moratz C., Harrison K., Kehrl J. H.
Archivum Immunologiae et Therapiae Experimentalis
|
2004
|
tom 52
|
nr 1
12
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Content available

Protective immunization of cattle with a BHV1 vector vaccine or a DNA vaccine both coding for the G protein of BRSV

63%
Schrijver R. S., Langedijk J. P. M., Keil G. M., Middel W. G. J., Maris-Veldhuis M., Van Oirschot J. T., Rijsewijk F. A. M.
Bulletin of the Veterinary Institute in Puławy
|
1998
|
tom 42
|
nr 1
13

Pharmacological evidence suggests that the lysozyme-PACAP receptor of Tetrahymena thermophila is a polycation receptor

63%
Keedy M., Yorgey N., Hilty J., Price A., Hassenzahl D., Kuruvilla H.
Acta Protozoologica
|
2003
|
tom 42
|
nr 1
14

Light-induced interaction of putative phosducin with Gbetagamma-subunits of G-protein in the ciliate Blepharisma japonicum

63%
Sobierajska K., Fabczak S.
Acta Protozoologica
|
2005
|
tom 44
|
nr 3
15

Chemokines, G proteins and natural killer cells

63%
Maghazachi A. A.
Archivum Immunologiae et Therapiae Experimentalis
|
2000
|
tom 48
|
nr 2
16

PACAP-38 signalling in Tetrahymena thermophila involves NO and cGMP

63%
Lucas J., Riddle M., Bartholomew J., Thomas B., Forni J., Nickerson L. E., Van Heukelum B., Paulick J., Kuruvilla H.
Acta Protozoologica
|
2004
|
tom 43
|
nr 1
17

Protozoa as model system for studies of sensory light transduction: photophobic response in the ciliate Stentor and Blepharisma

63%
Fabczak H.
Acta Protozoologica
|
2000
|
tom 39
|
nr 3
18

The GTPase domain of Galphao contributes to the functional interactions of Galphao with the promyelocytic leukemia zinc finger protein

51%
Won J. H., Ghil S. H.
Cellular and Molecular Biology Letters
|
2009
|
tom 14
|
nr 1
46-56
Go, one of the most abundant heterotrimeric G proteins in the brain, is classified as a member of the Gi/Go family based on its homology to Gi proteins. Recently, we identified promyelocytic leukemia zinc finger protein (PLZF) as a candidate downstream effector for the alpha subunit of Go (Gαo). Activated Gαo interacts with PLZF and augments its function as a repressor of transcription and cell growth. G protein-coupled receptor-mediated Gαo activation also enhanced PLZF function. In this study, we determined that the GTPase domain of Gαo contributes to Gαo:PLZF interaction. We also showed that the Gαo GTPase domain is important in modulating the function of PLZF. This data indicates that the GTPase domain of Gαo may be necessary for the functional interaction of Gαo with PLZF.
19

Structure of small G proteins and their regulators

51%
Paduch M., Jelen F., Otlewski J.
Acta Biochimica Polonica
|
2001
|
tom 48
|
nr 4
In recent years small G proteins have become an intensively studied group of regula­tory GTP hydrolases involved in cell signaling. More than 100 small G proteins have been identified in eucaryotes from protozoan to human. The small G protein superfamily includes Ras, Rho Rab, Rac, Sar1/Arf and Ran homologs, which take part in numerous and diverse cellular processes, such as gene expression, cytoskeleton re­organization, microtubule organization, and vesicular and nuclear transport. These proteins share a common structural core, described as the G domain, and significant sequence similarity. In this paper we review the available data on G domain structure, together with a detailed analysis of the mechanism of action. We also present small G protein regulators: GTPase activating proteins that bind to a catalytic G domain and increase its low intrinsic hydrolase activity, GTPase dissociation inhibitors that stabi­lize the GDP-bound, inactive state of G proteins, and guanine nucleotide exchange fac­tors that accelerate nucleotide exchange in response to cellular signals. Additionally, in this paper we describe some aspects of small G protein interactions with down­stream effectors.
20

Xanthine, xanthosine and its nucleotides: solution structures of neutral and ionic forms, and relevance to substrate properties in various enzyme systems and metabolic pathways

51%
Kulikowska E., Kierdaszuk B., Shugar D.
Acta Biochimica Polonica
|
2004
|
tom 51
|
nr 2
The 6-oxopurine xanthine (Xan, neutral form 2,6-diketopurine) differs from the cor­responding 6-oxopurines guanine (Gua) and hypoxanthine (Hyp) in that, at physio­logical pH, it consists of a = 1:1 equilibrium mixture of the neutral and monoanionic forms, the latter due to ionization of N(3)-H, in striking contrast to dissociation of the N(1)-H in both Gua and Hyp at higher pH. In xanthosine (Xao) and its nucleotides the xanthine ring is predominantly, or exclusively, a similar monoanion at physiological pH. The foregoing has, somewhat surprisingly, been widely overlooked in studies on the properties of these compounds in various enzyme systems and metabolic path­ways, including, amongst others, xanthine oxidase, purine phosphoribosyltrans- ferases, IMP dehydrogenases, purine nucleoside phosphorylases, nucleoside hydro- lases, the enzymes involved in the biosynthesis of caffeine, the development of xanthine nucleotide-directed G proteins, the pharmacological properties of alkyl- xanthines. We here review the acid/base properties of xanthine, its nucleosides and nucleotides, their N-alkyl derivatives and other analogues, and their relevance to studies on the foregoing. Included also is a survey of the pH-dependent helical forms of polyxanthylic acid, poly(X), its ability to form helical complexes with a broad range of other synthetic homopolynucleotides, the base pairing properties of xanthine in synthetic oligonucleotides, and in damaged DNA, as well as enzymes involved in circumventing the existence of xanthine in natural DNA.
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