title: A 16 amino-acid synthetic peptide, derived from human C3d, carries regulatory activity on in vitro phosphorylation of a cellular component of the human B lymphoma cells, Raji.
abstract: We present herein the first evidence that human C3 and, with a higher efficiency, trypsin-cleaved C3 enhanced in vitro phosphorylation of a cellular component, characterized by an apparent molecular weight of 105 kDa, pp105, present in the human B lymphoma cells, Raji. This regulatory activity was associated with C3d fragment generated in trypsin-cleaved C3. A 16 amino-acid peptide, carrying the LYNVEA sequence of C3d reacting with the C3d receptor (CR2), was synthetized. P16 enhanced, in a dose-dependent curve between 0.3 to 10 microM, in vitro phosphorylation of pp105, as well as C3d fragments present in trypsin-cleaved C3. A fibrinogen-related synthetic peptide of 15 amino acids, used as control, had no effect on pp105 phosphorylation. P16 and trypsin-cleaved C3 regulate pp105 phosphorylation through identical pathways. Thus, p16 represents the 16 amino-acid sequence of C3 which regulated in vitro phosphorylation of pp105.
authors.affiliation: Immunochimie des Antigènes de Membrane et des Interactions Cellulaires, Centre INSERM, Hôpital Saint-Antoine, Paris, France.
authors.forename: F
authors.initials: F
authors.lastname: Lyamani
authors.forename: A
authors.initials: A
authors.lastname: Gauffre
authors.forename: M
authors.initials: M
authors.lastname: Barel
authors.forename: A
authors.initials: A
authors.lastname: Fiandino-Tirel
authors.forename: J
authors.initials: J
authors.lastname: Hermann
authors.forename: R
authors.initials: R
authors.lastname: Frade
mesh_terms: D000595:Amino Acid Sequence; D002051:Burkitt Lymphoma; D002460:Cell Line; D015933:Complement C3d / Q000138:chemical synthesis / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000378:metabolism; D010455:Peptides / Q000138:chemical synthesis / Q000494:pharmacology*; D010750:Phosphoproteins / Q000302:isolation & purification; D010766:Phosphorylation
chemical_list: D009363:Neoplasm Proteins; D010455:Peptides; D010750:Phosphoproteins; D015933:Complement C3d