title: Ontogeny of membrane-bound protein phosphorylating systems in the rat.
abstract: The ontogeny of the major intrinsic phosphoproteins in membrane fractions prepared from cerebral cortex was studied in the rat. The apparent membrane content of 4 phosphoproteins increased markedly over the period 10-15 days after birth, i.e. coinciding with the onset of synaptogenesis. Two of these proteins (molecular weights 79,000 and 86,000) were phosphorylated in cyclic AMP-dependent reactions, and two (molecular weights 50,000 and 162,000) were phosphorylated in reactions dependent on Ca2+ + cytosol extract. The apparent content of other acceptor proteins phosphorylated in analogous reactions increased more gradually from birth to adulthood. In contrast the apparent membrane content of a protein of 47,000 daltons, which was phosphorylated in a reaction requiring Ca2+ only, was relatively very high at birth and until 15 days of age, but then declined 6-fold until adulthood was reached. The relative distribution of the intrinsic phosphoproteins in several particulate fractions was also compared in 1- and 19-day-old rats. In 1-day-old animals the phosphoprotein of 47,000 daltons was found predominantly in a light membrane fraction, but at 19 days it was only just discernible in the equivalent fraction and was found instead in heavier fractions.
mesh_terms: D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D002458:Cell Fractionation; D002462:Cell Membrane / Q000201:enzymology; D002540:Cerebral Cortex / Q000201:enzymology* / Q000254:growth & development; D003600:Cytosol / Q000201:enzymology; D008565:Membrane Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats
chemical_list: D008565:Membrane Proteins; D011494:Protein Kinases