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Modulation of Phosphorylation of a 30‐kD Polyribosomal Protein (pp30) by ACTH and Spermine: Comparison with Modulation of Brain Protein Synthesis
Author(s) -
Schrama L. H.,
Frankena H.,
Edwards P. M.,
Schotman P.
Publication year - 1984
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1984.tb06097.x
Subject(s) - modulation (music) , spermine , phosphorylation , chemistry , biochemistry , physics , acoustics , enzyme
Gel electrophoretic separation of proteins phosphorylated in a postmitochondrial supernatant fraction of brain in the presence of spermine or adrenocorticotropin (ACTH) indicated modulation in only one region (30 kD) of the gel. The 30‐kD (pp30) protein together with enzyme activity catalyzing its phosphorylation and sensitivity of the phosphorylation to spermine and ACTH were retained in a free polyribosomal fraction of this extract. ACTH(11–24) inhibited phosphorylation at all the spermine or Mg 2+ concentrations tested. Structure‐activity studies revealed that the inhibitory activity within ACTH(l–24) resides in the sequences ACTH(11–24), (5–18, 17 Lys, 18 Lys)‐NH 2 , (15–24), (7–16)‐NH 2 , and (1–16)‐NH 2 and can also be found in certain polylysine fragments. Phosphorylation under conditions suitable for measuring protein synthesis revealed only one phosphoprotein (pp30), sensitive to both ACTH(15–24) and spermine. The possibility of a relationship between modulation of pp30 phosphorylation and modulation of brain cell‐free protein synthesis is discussed in relation to the effects of ACTH, spermine, and Mg 2 + .