ADP-ribosylation of myelin basic protein and inhibition of phospholipid vesicle aggregation.
Four isoforms of myelin basic protein (MBP) from chicken brain were ADP-ribosylated by chicken heterophil ADP-ribosyltransferase. The 21-kD isoform was the most preferential substrate of this transferase. With this isoform, the Km values were estimated to be 330 mumol/l for NAD and 30 mumol/l for MBP, and the optimal pH for ADP-ribosylation was 8.5. The stoichiometry of ADP-ribose incorporation into 21-kD MBP was 3.5 mol of ADP-ribose/mol MBP. We found the inhibition of ADP-ribosylation of MBP by hydroxylamine and L-arginine indicating that this modification was likely to be mediated by arginine residues. Proteolytic peptide maps of ADP-ribosylated MBP by chicken ADP-ribosyltransferase and cholera toxin showed partially different radio active bands. When 21-kD MBP was ADP-ribosylated by chicken transferase, the potential for phospholipid vesicle aggregation was reduced in proportion of the degree of ADP-ribosylation. The possibility that ADP-ribosylation of MBP may control stabilization of myelin through regulation of its affinity for phospholipid in vivo would need to be considered.
Yamamori
C
C
Department of Psychiatry, Shimane Medical University, Izumo, Japan.
Terashima
M
M
Ishino
H
H
Shimoyama
M
M
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism*; D008970:Molecular Weight; D004676:Myelin Basic Protein / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D009504:Neutrophils / Q000201:enzymology; D010743:Phospholipids / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
D008081:Liposomes; D004676:Myelin Basic Protein; D010743:Phospholipids; D009243:NAD; D000246:Adenosine Diphosphate Ribose; D011065:Poly(ADP-ribose) Polymerases