Among T3 receptors, TRα1 is ubiquitous and its deletion or a specific expression of a dominant-negative TRα1 isoform in Sertoli cell leads to an increase in testis weight and sperm production. The identification of a 43-kDa truncated form of the nuclear receptor TRα1 (p43) in the mitochondrial matrix led us to test the hypothesis that this mitochondrial transcription factor could regulate Serto...

In previous studies, we characterized a new hormonal pathway involving a mitochondrial T3 receptor (p43) acting as a mitochondrial transcription factor. In in vitro and in vivo studies, we have shown that p43 increases mitochondrial transcription and mitochondrial biogenesis. In addition, p43 overexpression in skeletal muscle stimulates mitochondrial respiration and induces a shift in metabolic...

p43, a glycoprotein of pea chloroplast (ct), acts as an accessory protein of pea chloroplast DNA polymerase. p43 binds to DNA, binds to ct-DNA polymerase and stimulates the ct-DNA polymerase activity. In the work presented here, the C-terminal domain of p43 (p22) has been overexpressed in E. coli. South Western analysis reveals that the recombinant p22 lacks in DNA binding activity. However, th...

Hepatitis C virus (HCV) causes chronic hepatitis leading to liver fibrosis and autoimmune diseases. AIMP1/p43 is a multifunctional protein initially known as a cofactor of aminoacyl tRNA synthetase complex. Its function includes negative regulation of TGF-β signaling and suppression of Lupus-like autoimmune disease by inhibition of surface expression of gp96. HCV E2 was shown to directly intera...

Telomere replication of eukaryotic chromosomes is achieved by a specialized enzyme, the telomerase. Although the biochemistry of end-replication is well understood, little is known about the organization of the end-replication machinery, its regulation throughout the cell cycle or the biological function of the telomerase-associated proteins. Here we investigate the function of the telomerase-a...

Challenge of neutrophils with concanavalin A (ConA), formyl-methionyl-leucyl-phenylalanine (FMLP), and phorbol 12-myristate 13-acetate (PMA) induced the tyrosine phosphorylation of several proteins. Among these proteins we have identified two mitogen-activated protein kinase (MAPK) isoforms of 43 kDa (p43 MAPK) and 45 kDa (p45 MAPK) molecular mass. Moreover here we show that: (1) FMLP induced t...

Human placental isoferritin (PLF) is known to exert an immunosuppressive activity in vitro and is involved in the down-regulation of the maternal immune system during pregnancy. We have investigated the presence of PLF in the human embryo and early fetus and its secretion into amniotic fluid (AF) and fetal blood. Immunohistochemistry was performed on 25 normal embryos and fetuses, at 7-22 weeks...

In vertebrates, skeletal muscle myofibers display different contractile and metabolic properties associated with different mitochondrial content and activity. We have previously identified a mitochondrial triiodothyronine receptor (p43) regulating mitochondrial transcription and mitochondrial biogenesis. When overexpressed in skeletal muscle, it increases mitochondrial DNA content, stimulates m...

In previous studies, we have characterized a new hormonal pathway involving a mitochondrial T3 receptor (p43) acting as a mitochondrial transcription factor and consequently stimulating mitochondrial activity and mitochondrial biogenesis. We have established the involvement of this T3 pathway in the regulation of in vitro myoblast differentiation. We have generated mice overexpressing p43 under...