Synthesis and phosphorylation of the glial fibrillary acidic protein during brain development: A tissue slice study

✍ Scribed by Michael J. Noetzel

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 834 KB
• Volume: 3
• Category: Article
• ISSN: 0894-1491
• DOI: 10.1002/glia.440030603

✦ Synopsis

Brain slices were incubated with either I3H1 amino acids or [32Pl orthophosphate in order to characterize the synthesis and phosphorylation of the glial fibrillary acidic protein (GFAP) in the rat nervous system. The incorporation of l3H1 amino acids into GFAP was found to increase significantly during earl), postnatal development, reaching a peak of activity on day 5 of life and then declining over the next 2 weeks. Concomitant with this peak of synthetic activity the content of GFAP m rat brain was also observed to increase dramatically. GFAP continued to accumulate in brain through postnatal day 30 despite a decrease in the synthesis of the protein. These results indicate that the increase in GFAP during the first month of life cannot be ascribed solely to the rate of GFAP synthesis. The findings are consistent with the hypothesis that during later stages of astrocytic development the accumulation of GFAP may bt: primarily dependent upon a low rate of protein degradation. The pattern of GFAP phosphorylation in the developing rat brain differed from that observed for the incorporation of I3H] amino acids. The peak incorporation of 32P into GFAP occurred on postnatal day 10 at a time when synthesis of the protein had declined by 43%. These findings suggest that during development phosphorylation of GFAP is mediated by factors different from those directing its synthesis. In addition, phsophorylation of GFAP did not alter its solubility in cytoskeletal preparations indicating that GFAP phosphorylation is probably not a major regulatory mechanism in disassembly of the astroglial filaments.