Novel consensus sequence for the Golgi apparatus casein kinase, revealed using proline-rich protein-1 (PRP1)-derived peptide substrates

• Published in: Biochemical journal Vol. 351 Pt 3; no. 3; pp. 765 - 768
• Main Authors: Brunati, A M, Marin, O, Bisinella, A, Salviati, A, Pinna, L A
• Format: Journal Article
• Language: English
• Published: England 01-11-2000
• Subjects: Amino Acid Sequence; Casein Kinases; Consensus Sequence; Golgi Apparatus - enzymology; Kinetics; Molecular Sequence Data; Peptides - metabolism; Proline-Rich Protein Domains; Protein Kinases - chemistry; Protein Kinases - isolation & purification; Protein Kinases - metabolism; Substrate Specificity
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/0264-6021:3510765

Previous studies have shown that the Golgi apparatus casein kinase (G-CK) recognizes phosphoacceptor sites specified by the triplet SXE/Sp, which is found in several phosphoproteins, besides casein itself. In the present study, we report that G-CK can phosphorylate, with comparable efficiency, sequences surrounding Ser-22 of salivary proline-rich protein-1 (PRP1), which do not conform to the SXE/Sp motif. By using a series of peptide substrates derived from the PRP1 Ser-22 site, we also have shown that the optimal consensus sequence recognized by G-CK in this case was SXQXX(D/E)3, where the acidic residues at positions n+5 to n+7 and, to a lesser extent, the glutamine residue at position n+2 are the critical determinants.