Phosphorylation and O-glycosylation sites of bovine chromogranin A from adrenal medullary chromaffin granules and their relationship with biological activities.
Bovine adrenal medullary chromogranin A, the major soluble component of chromaffin granules, is a phosphorylated glycoprotein. In the present work, phosphorylation and glycosylation sites were determined using mild proteolysis, peptide separation, microsequencing, and mass analysis by electrospray and matrix-assisted laser desorption ionization time-of-flight techniques. Seven post-translational modification sites were detected. Two O-linked glycosylation sites, each consisting of the trisaccharide NeuAcalpha2-3Galbeta1-3GalNAcalpha1, were located in the middle part of the protein, on Ser186 and on Thr231. The former residue is present in the antibacterial peptide named chromacin. Four phosphorylation sites were located on serine residues at positions Ser81 in the N-terminal region of the protein and Ser307, Ser372, and Ser376 in the C-terminal end. One additional phosphorylation site was found on the tyrosine residue at position Tyr173, the N-terminal amino acid of chromacin. With the exception of the phosphorylation on Tyr173, all of the other post-translational modifications are located on highly conserved chromogranin A regions, implying some biological importance.
Strub
J M
JM
Institut National de la Santé et de la Recherche Médicale, Unité 338 de Biologie de la Communication Cellulaire, 67084 Strasbourg Cedex, France.
Sorokine
O
O
Van Dorsselaer
A
A
Aunis
D
D
Metz-Boutigue
M H
MH
D000313:Adrenal Medulla / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002837:Chromaffin Granules / Q000378:metabolism*; D053379:Chromogranin A; D002864:Chromogranins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D000939:Epitopes / Q000032:analysis; D006031:Glycosylation; D006801:Humans; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin
C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins; D000939:Epitopes; D010446:Peptide Fragments; D011994:Recombinant Proteins; C506155:chromogranin A, mouse; D014357:Trypsin