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Last name: ORTONNE
First name: Jean-Paul
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We showed previously that Lyn is a substrate for caspases, a family of cysteine proteases, involved in the regulation of apoptosis and inflammation. Here, we report that expression of the caspase-cleaved form of Lyn (LynDeltaN), in mice, mediates a chronic inflammatory syndrome resembling human psoriasis. Genetic ablation of TNF receptor 1 in a...
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IGF1 plays a key role in the development and growth of multiple tumors and in the prevention of apoptosis. In melanoma cells, IGF1 has been shown to mediate resistance to anoikis-induced apoptosis. However, the effect of IGF1 on other proapoptotic stimuli has never been reported. Further, the molecular mechanisms by which IGF1 mediates its...
Embryonic stem (ES) cell lines can be expanded indefinitely in culture while maintaining their potential to differentiate into any cell type. During embryonic development, the skin forms as a result of reciprocal interactions between mesoderm and ectoderm. Here, we report the in vitro differentiation and enrichment of keratinocytes from murine...
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Melanins are synthesized in melanocytes within specialized organelles called melanosomes. Numerous studies have shown that the pH of melanosome plays a key role in the regulation of melanin synthesis. However, until now, acute regulation of melanosome pH by a physiological stimulus has never been demonstrated. In the present study, we show that...
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In mouse follicular melanocytes, production of eumelanins (brown-black pigments) and pheomelanins (yellow-brownish pigments) is under the control of two intercellular signaling molecules that exert opposite actions, alpha-melanocyte-stimulating hormone (alphaMSH) which preferentially increases the synthesis of eumelanins, and agouti signal...
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Loss of tumor-suppressive pathways that control cellular senescence is a crucial step in malignant transformation. Spleen tyrosine kinase (Syk) is a cytoplasmic tyrosine kinase that has been recently implicated in tumor suppression of melanoma, a deadly skin cancer derived from pigment-producing melanocytes. However, the mechanism by which Syk...