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Charpentier Stéphane


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tél : 02.38.25.55.96 - fax : 02.38.25.55.83

Publications

2013   Références trouvées : 1

Mollet L., Robinet P., Dubois M., Aurouet A., Normand T., Charpentier S., Sureau A., Grandclement C., Garnache-Ottou F., Deconinck E., Brulé F., Rohrlich P.S. and Legrand A.  (2013)

Opposing Mcl-1, the GALIG proapoptotic gene is upregulated as neutrophils die and underexpressed in Acute Myeloid Leukemia cells

Molecular Immunology 56 (1-2) 123-128
GALIG gene expression induces apoptosis in cultured cells through a pathway still under investigation. It is highly expressed in leukocytes but weakly detectable in bone marrow, suggesting a role in the myeloid lineage homeostasis. We show here that GALIG-induced cell death is counteracted by the overexpression of MCL-1, a pro-survival member of the Bcl2 family. Moreover, during spontaneous neutrophil apoptosis, a substantial increase in GALIG gene expression is observed : GALIG still opposes MCL-1. Finally, in bone marrow and peripheral blood cells from patients with Acute Myeloid Leukemia type 2, the level of GALIG transcripts is massively down-regulated when compared to their normal counterparts, while MCL-1 is expressed to the same extent. These data suggest that GALIG could be a key player in the cell death pathway involved in leukocytes homeostasis and myeloid malignancies.

GALIG gene expression induces apoptosis in cultured cells through a pathway still under investigation. It is highly expressed in leukocytes but weakly detectable in bone marrow, suggesting a role in the myeloid lineage homeostasis. We show here that GALIG-induced cell death is counteracted by the overexpression of MCL-1, a pro-survival member of the Bcl2 family. Moreover, during spontaneous neutrophil apoptosis, a substantial increase in GALIG gene expression is observed : GALIG still opposes MCL-1. Finally, in bone marrow and peripheral blood cells from patients with Acute Myeloid Leukemia type 2, the level of GALIG transcripts is massively down-regulated when compared to their normal counterparts, while MCL-1 is expressed to the same extent. These data suggest that GALIG could be a key player in the cell death pathway involved in leukocytes homeostasis and myeloid malignancies.


2010   Références trouvées : 1

Robinet, P., Mollet, L., Gonzalez, P., Normand, T., Charpentier, S., Brule, F., Dubois, M. & Legrand, A.  (2010)

The mitogaligin protein is addressed to the nucleus via a non-classical localization signal.

Biochem. Biophys. Res. Commun. 392, 53-57.


2009   Références trouvées : 2

Sennepin, A.D., Charpentier, S., Normand, T., Sarre, C., Legrand, A. & Mollet, L.M.  (2009)

Multiple reprobing of Western blots after inactivation of peroxidase activity by its substrate, hydrogen peroxide.

Anal. Biochem. 393, 129-131.

Gonzalez, P., Robinet, P., Charpentier, S., Mollet, L., Normand, T., Dubois, M. & Legrand, A.  (2009)

Apoptotic activity of a nuclear form of mitogaligin, a cell death protein.

Biochem. Biophys. Res. Commun. 378, 816-820.


2007   Références trouvées : 1

Gonzalez, P ; Duneau, M ; Charpentier, S ; Normand, T ; Mollet, L ; Dubois, M ; Legrand, A  (2007)

Destabilization of membranes containing cardiolipin or its precursors by peptides derived from mitogaligin, a cell death protein

Biochemistry 46 (25) 7374-7382
Galig, a gene embedded within the galectin-3 gene, induces cell death when transfected in human cells. This death is associated with cell shrinkage, nuclei condensation, and aggregation of mitochondria. Galig contains two different overlapping open reading frames encoding two unrelated proteins. Previous observations have shown that one of these proteins, named mitogaligin, binds to mitochondria and promotes the release of cytochrome c. However, the mechanism of action of this cytotoxic protein remains still obscure.

Galig, a gene embedded within the galectin-3 gene, induces cell death when transfected in human cells. This death is associated with cell shrinkage, nuclei condensation, and aggregation of mitochondria. Galig contains two different overlapping open reading frames encoding two unrelated proteins. Previous observations have shown that one of these proteins, named mitogaligin, binds to mitochondria and promotes the release of cytochrome c. However, the mechanism of action of this cytotoxic protein remains still obscure.


2005   Références trouvées : 1

Duneau, M ; Boyer-Guittaut, M ; Gonzalez, P ; Charpentier, S ; Normand, T ; Dubois, M ; Raimond, J ; Legrand, A  (2005)

Galig, a novel cell death gene that encodes a mitochondrial protein promoting cytochrome c release

Experimental Cell Research 302 (2) 194-205
Galectin-3 internal gene (Galig) was recently identified as an internal gene transcribed from the second intron of the human galectin-3 gene that is implicated in cell growth, cell differentiation, and cancer development. In this study, we show that galig expression causes morphological alterations in human cells, such as cell shrinkage, cytoplasm vacuolization, nuclei condensation, and ultimately cell death. These alterations were associated with extramitochondrial release of cytochrome c, a known cell death effector.

Galectin-3 internal gene (Galig) was recently identified as an internal gene transcribed from the second intron of the human galectin-3 gene that is implicated in cell growth, cell differentiation, and cancer development. In this study, we show that galig expression causes morphological alterations in human cells, such as cell shrinkage, cytoplasm vacuolization, nuclei condensation, and ultimately cell death. These alterations were associated with extramitochondrial release of cytochrome c, a known cell death effector.


2001   Références trouvées : 1

Guittaut, M ; Charpentier, S ; Normand, T ; Dubois, M ; Raimond, J ; Legrand, A  (2001)

Identification of an internal gene to the human galectin-3 gene with two different overlapping reading frames that do not encode galectin-3

Journal of Biological Chemistry 276 (4) 2652-2657
We previously reported that alternative transcripts were initiated within the second intron of the human Galectin-3 gene (LGALS3), We now demonstrate that these transcripts arise from an internal gene embedded within LGALS3 and named galig (Galectin-3 internal gene). Tissue-specific expression of galig was assayed by screening of several human tissues. Contrary to LGALS3, galig appears to be tightly regulated and principally activated in leukocytes from peripheral blood. Cloning and characterization of galig transcripts revealed that they contain two out-of-frame overlapping open-reading frames (ORFs). Transfection of expression vectors encoding enhanced green fluorescent protein (EGFP) chimeras indicated that both ORFs could be translated in proteins unrelated to Galectin-3. The ORF1 polypeptide targets EGFP to cytosol and nucleus whereas ORF2 targets EGFP to mitochondria. These results revealed the exceptional genetic organization of the LGALS3 locus.

We previously reported that alternative transcripts were initiated within the second intron of the human Galectin-3 gene (LGALS3), We now demonstrate that these transcripts arise from an internal gene embedded within LGALS3 and named galig (Galectin-3 internal gene). Tissue-specific expression of galig was assayed by screening of several human tissues. Contrary to LGALS3, galig appears to be tightly regulated and principally activated in leukocytes from peripheral blood. Cloning and characterization of galig transcripts revealed that they contain two out-of-frame overlapping open-reading frames (ORFs). Transfection of expression vectors encoding enhanced green fluorescent protein (EGFP) chimeras indicated that both ORFs could be translated in proteins unrelated to Galectin-3. The ORF1 polypeptide targets EGFP to cytosol and nucleus whereas ORF2 targets EGFP to mitochondria. These results revealed the exceptional genetic organization of the LGALS3 locus.


1998   Références trouvées : 1

Charpentier, S ; Amiche, M ; Mester, J ; Vouille, V ; Le Caer, JP ; Nicolas, P ; Delfour, A  (1998)

Structure, synthesis, and molecular cloning of dermaseptins B, a family of skin peptide antibiotics

Journal of Biological Chemistry 273 (24) 14690-14697
Analysis of antimicrobial activities that are present in the skin secretions of the South American frog Phyllomedusa bicolor revealed six polycationic (lysine-rich) and amphipathic alpha-helical peptides, 24-33 residues long, termed dermaseptins B1 to B6, respectively, Prepro-dermaseptins B all contain an almost identical signal peptide, which is followed by a conserved acidic propiece, a processing signal Lys-Arg, and a dermaseptin progenitor sequence. The 22-residue signal peptide plus the first 3 residues of the acidic propiece are encoded by conserved nucleotides encompassed by the first coding exon of the dermaseptin genes. The 25-residue amino-terminal region of prepro-dermaseptins B shares 50% identity with the corresponding region of precursors for D-amino acid containing opioid peptides or for antimicrobial peptides originating from the skin of distantly related frog species. The remarkable similarity found between prepro-proteins that encode end products with strikingly different sequences, conformations, biological activities and modes of action suggests that the corresponding genes have evolved through dissemination of a conserved "secretory cassette" exon.

Analysis of antimicrobial activities that are present in the skin secretions of the South American frog Phyllomedusa bicolor revealed six polycationic (lysine-rich) and amphipathic alpha-helical peptides, 24-33 residues long, termed dermaseptins B1 to B6, respectively, Prepro-dermaseptins B all contain an almost identical signal peptide, which is followed by a conserved acidic propiece, a processing signal Lys-Arg, and a dermaseptin progenitor sequence. The 22-residue signal peptide plus the first 3 residues of the acidic propiece are encoded by conserved nucleotides encompassed by the first coding exon of the dermaseptin genes. The 25-residue amino-terminal region of prepro-dermaseptins B shares 50% identity with the corresponding region of precursors for D-amino acid containing opioid peptides or for antimicrobial peptides originating from the skin of distantly related frog species. The remarkable similarity found between prepro-proteins that encode end products with strikingly different sequences, conformations, biological activities and modes of action suggests that the corresponding genes have evolved through dissemination of a conserved "secretory cassette" exon.


1996   Références trouvées : 1

Charpentier, S ; Jarvie, KR ; Severynse, DM ; Caron, MG ; Tiberi, M  (1996)

Silencing of the constitutive activity of the dopamine D1B receptor

Journal of Biological Chemistry 271 (45) 28071-28076
Recently, we have shown that the dopamine D1B/D5 receptor displays binding and coupling properties that are reminiscent of those of the constitutively activated G protein-coupled receptors when compared with the related D1A/D1 receptor subtype (Tiberi, M., and Caron, M. G. (1994) J. Biol. Chem. 269, 27925-27931). The carboxyl-terminal region of the third cytoplasmic loop of several G protein coupled receptors has been demonstrated to be important for the regulation of the equilibrium between inactive and active receptor conformations. In this cytoplasmic region, the primary structure of dopamine D1A and D1B receptors differs by only two residues : Phe(264)/Arg(266) present in D1A receptor compared with Ile(288)/Lys(290) in the D1B receptor.

Recently, we have shown that the dopamine D1B/D5 receptor displays binding and coupling properties that are reminiscent of those of the constitutively activated G protein-coupled receptors when compared with the related D1A/D1 receptor subtype (Tiberi, M., and Caron, M. G. (1994) J. Biol. Chem. 269, 27925-27931). The carboxyl-terminal region of the third cytoplasmic loop of several G protein coupled receptors has been demonstrated to be important for the regulation of the equilibrium between inactive and active receptor conformations. In this cytoplasmic region, the primary structure of dopamine D1A and D1B receptors differs by only two residues : Phe(264)/Arg(266) present in D1A receptor compared with Ile(288)/Lys(290) in the D1B receptor.


1994   Références trouvées : 1

Charpentier, S ; Sagan, S ; Naim, M ; Delfour, A ; Nicolas, P  (1994)

Mechanisms of d-opioid receptor selection by the address domain of dermenkephalin

European Journal of Pharmacology-Molecular Pharmacology Section 266 (2) 175-180
Dermenkephalin (Tyr-D-Met-Phe-His-Leu-Met-AspNH(2)) is a highly potent and selective d-opioid peptide isolated from frog skin. It was recently recognized that the C-terminus His(4)-Leu(5)-Met(6)-Asp(7)NH(2) of dermenkephalin was responsible for the addressing of the peptide towards the d-opioid receptor. In order to investigate the role played by residues 4, 5 and 6 in this 'd address', we synthesized and evaluated 20 new analogues for their ability to displace tritiated ligands from mu- and d-opioid sites. Results showed that position 4 of dermenkephalin contributes to 6 selectivity independently of d-opioid receptor binding by preventing a high affinity mu binding. Position 5 requires a hydrophobic side chain to enhance d affinity. A high d affinity was obtained with any amino acids introduced in position 6 suggesting that residue 6 serves as a neutral spacer. Thus, the main features responsible for the high d-opioid selectivity of dermenkephalin are electrostatic repulsions with the mu-opioid receptor, additional hydrophobic interactions with the d-opioid receptor and folding of the C-terminal domain.

Dermenkephalin (Tyr-D-Met-Phe-His-Leu-Met-AspNH(2)) is a highly potent and selective d-opioid peptide isolated from frog skin. It was recently recognized that the C-terminus His(4)-Leu(5)-Met(6)-Asp(7)NH(2) of dermenkephalin was responsible for the addressing of the peptide towards the d-opioid receptor. In order to investigate the role played by residues 4, 5 and 6 in this ’d address’, we synthesized and evaluated 20 new analogues for their ability to displace tritiated ligands from mu- and d-opioid sites. Results showed that position 4 of dermenkephalin contributes to 6 selectivity independently of d-opioid receptor binding by preventing a high affinity mu binding. Position 5 requires a hydrophobic side chain to enhance d affinity. A high d affinity was obtained with any amino acids introduced in position 6 suggesting that residue 6 serves as a neutral spacer. Thus, the main features responsible for the high d-opioid selectivity of dermenkephalin are electrostatic repulsions with the mu-opioid receptor, additional hydrophobic interactions with the d-opioid receptor and folding of the C-terminal domain.


1993   Références trouvées : 2

Naim, M ; Charpentier, S ; Nicolas, P ; Baron, D   (1993)

Quantitative two-dimensional NMR study of dermenkephalin, a highly potent and selective d-opioid peptide

Biopolymers 33 (12) 1889-1900
Dermenkephalin, H-Tyr-(D)Met-Phe-His-Leu-Met-Asp-NH2, a highly potent and selective d-opioid peptide isolated from frog skin, was studied in DMSO-d(6) solution by two-dimensional nmr spectroscopy, including the determination of NH temperature coefficients, the evaluation of (3)J coupling constants from phase-sensitive correlated spectroscopy (COSY) and the volumes of nuclear Overhauser effect (NOE) correlations. The two-dimensional NOE spectroscopy (NOESY) spectrum of dermenkephalin revealed sequential, medium-, and long-range effects. To put this information on a quantitative basis, special attention was devoted to J cross-peak suppression, quantification of the NOE volumes and analysis of the overlaps, normalization of the NOEs against diagonal peaks and H beta beta, geminal interactions.

Dermenkephalin, H-Tyr-(D)Met-Phe-His-Leu-Met-Asp-NH2, a highly potent and selective d-opioid peptide isolated from frog skin, was studied in DMSO-d(6) solution by two-dimensional nmr spectroscopy, including the determination of NH temperature coefficients, the evaluation of (3)J coupling constants from phase-sensitive correlated spectroscopy (COSY) and the volumes of nuclear Overhauser effect (NOE) correlations. The two-dimensional NOE spectroscopy (NOESY) spectrum of dermenkephalin revealed sequential, medium-, and long-range effects. To put this information on a quantitative basis, special attention was devoted to J cross-peak suppression, quantification of the NOE volumes and analysis of the overlaps, normalization of the NOEs against diagonal peaks and H beta beta, geminal interactions.

Sagan, S ; Charpentier, S ; Naim, M ; Delfour, A ; Nicolas, P   (1993)

Opioid peptides from amphibian skin : contribution of the amino acids of the "address" domain to the d-selectivity of dermenkephalin

Peptides 1992 645-646 - Editor(s) : Schneider, CH ; Eberle, AN (ESCOM, Leiden)


1992   Références trouvées : 1

Sagan, S ; Charpentier, S ; Delfour, A ; Amiche, M ; Nicolas, P  (1992)

The aspartic acid in deltorphin I and dermenkephalin determines correct addressing to the d-opioid receptor independently of receptor binding

Biochemical and Biophysical Research Communications 187 1203-1210


1991   Références trouvées : 2

Sagan, S ; Charpentier, S ; Corbett, AD ; Amiche, M ; Delfour, A ; Nicolas, P ; Kosterlitz, HW   (1991)

Opioid activity of some analogues of dermenkephalin and deltorphin I in binding assays and bioassays

British Journal of Pharmacology 104 225p

Simon, P ; Charpentier, S ; Costentin, J  (1991)

An automated method for the assessment of spontaneous and stereotyped climbing behavior in mice : effects of the selective D(1)- and D(2)- dopamine receptor agonists SKF-38393 and RU-24926 and their association

Methods and Findings in Experimental and Clinical Pharmacology 13 (2) 99-104
A video-tracking technique has been used for the evaluation of climbing behavior in mice. An automated image analysis system, the Videotrack 512 (Electronique Lyonnaise), was adapted for this specific application. This allowed distinguishing between spontaneous climbing and stereotyped climbing. The activity duration of mice was simultaneously measured. In order to validate this method, in the present study the ability of apomorphine to induce climbing in mice, and the effects of the D1-dopamine receptor agonist SKF-38393 and the D2-dopamine agonist RU-24926 and their association were investigated.

A video-tracking technique has been used for the evaluation of climbing behavior in mice. An automated image analysis system, the Videotrack 512 (Electronique Lyonnaise), was adapted for this specific application. This allowed distinguishing between spontaneous climbing and stereotyped climbing. The activity duration of mice was simultaneously measured. In order to validate this method, in the present study the ability of apomorphine to induce climbing in mice, and the effects of the D1-dopamine receptor agonist SKF-38393 and the D2-dopamine agonist RU-24926 and their association were investigated.


1990   Références trouvées : 1

Bralet, J ; Mossiat, C ; Lecomte, JM ; Charpentier, S ; Gros, C ; and Schwartz, JC   (1990)

Diuretic and natriuretic responses in rats treated with enkephalinase inhibitors

European Journal of Pharmacology 179 (1-2) 57-64


Mots-clés

Maître de conférences , Mort cellulaire programmée