Light Exposue Activates Retina Ganglion Cell Lysophosphatidic Acid Acyl Transferase and Phosphatidic Acid Phosphatase by a c-fos-Dependent Mechanism

Authors

  • G. A. de Arriba Zerpa,

    1. CIQUIBIC (CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba * INIBIBB (CONICET), Universidad Nacional del Sur, Bahia Blanca, Argentina
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  • M. E. Guido,

    1. CIQUIBIC (CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba * INIBIBB (CONICET), Universidad Nacional del Sur, Bahia Blanca, Argentina
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  • D. F. Bussolino,

    1. CIQUIBIC (CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba * INIBIBB (CONICET), Universidad Nacional del Sur, Bahia Blanca, Argentina
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  • S. J. Pasquare,

    1. CIQUIBIC (CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba * INIBIBB (CONICET), Universidad Nacional del Sur, Bahia Blanca, Argentina
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  • P. I. Castagnet,

    1. CIQUIBIC (CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba * INIBIBB (CONICET), Universidad Nacional del Sur, Bahia Blanca, Argentina
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  • N. M. Giusto,

    1. CIQUIBIC (CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba * INIBIBB (CONICET), Universidad Nacional del Sur, Bahia Blanca, Argentina
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  • B. L. Caputto

    1. CIQUIBIC (CONICET), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba * INIBIBB (CONICET), Universidad Nacional del Sur, Bahia Blanca, Argentina
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  • Abbreviations used : AT II, lysophosphatidate acyl transerase ; LPA, lysophosphatidic acid ; NEM, N-ethylmaleimide ; PA, phosphatidic acid ; PAPase, phosphatidate phosphohydrolase ; PBS, sodium phosphate buffer ; PSS, phosphatidylserine synthase ; PTA, phosphotungstic acid ; PtdCho, phosphatidylcholine ; PtdEtn, phosphatidylethanolamine ; PtdIns, phosphatidylinositol ; PtdSer, phosphatidylserine ; TCA, trichloroacetic acid.

Address correspondence and reprint requests to Dr. B. L. Caputto at Departamento de Química Biológica, Facultad de Ciencias Químicas, Pabellón Argentina, Ciudad Universitaria, 5000 Córdoba, Argentina.

Abstract

Abstract : We previously reported that the biosynthesis of phospholipids in the avian retina is altered by light stimulation, increasing significantly in anglion cells in light and in photoreceptor cells in dark. In the present work, we have determined that light significantly increases the incorporation of [3H]glycerol into retina ganglion cell glycerophospholipids in vivo by a Fos-dependent mechanism because an oligonucleotide antisense to c-fos mRNA substantially blocked the light-dark differences. We also studied in viro the enzyme activities of phosphatidate phosphohydrolase (PAPase), lysophosphatidate acyl transferase (AT II), and phosphatidylserine synthase from retinas of chickens exposed to light or dark. Higher PAPase I and AT II activities were found in incubations of retinal ganglion cells from animals exposed to light ; no increase was observed in preparations obtained from light-exposed animals reated with the c-fos antisense oligonucleotide. No light-dark differences were found in phosphatidylserine synthase activity. These findings support the idea that a coordinated photic regulation of PAPase I and AT II is taking place in retina ganglion cells. This constitutes a reasonable mechanism to obtain an overall increased synthesis of glycerophospholipids in stimulated cells that is mediated by the expression of Fos-like proteins.

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