Premium
Synthesis and phosphorylation of the glial fibrillary acidic protein during brain development: A tissue slice study
Author(s) -
Noetzel Michael J.
Publication year - 1990
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.440030603
Subject(s) - glial fibrillary acidic protein , biology , phosphorylation , gfap stain , amino acid , protein phosphorylation , biochemistry , astrocyte , protein biosynthesis , central nervous system , medicine , endocrinology , microbiology and biotechnology , immunohistochemistry , immunology , protein kinase a
Abstract Brain slices were incubated with either [ 3 H] amino acids or [ 32 P] orthophosphate in order to characterize the synthesis and phosphorylation of the glial fibrillary acidic protein (GFAP) in the rat nervous system. The incorporation of [ 3 H] amino acids into GFAP was found to increase significantly during early 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 in 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 be 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 [ 3 H] amino acids. The peak incorporation of 32 P 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.