Golgi apparatus mammary gland casein kinase: monitoring by a specific peptide substrate and definition of specificity determinants.
The casein kinase from the Golgi apparatus of lactating mammary gland (GEF-CK) is distinct from ubiquitous 'casein kinases' termed protein kinases CK1 and CK2 and appears to define a family of secretory pathways protein kinases that phosphorylate seryl residues followed by an acidic residue at position +2. In this report we show that a new synthetic peptide substrate derived from beta-casein (beta[28-40]) is suitable for the fast, efficient and selective monitoring of GEF-CK, being unaffected by CK1 and CK2, and we define the consensus sequence of this protein kinase as being Ser-Xaa-Glu/SerP, distinct from that of CK2 (Ser/Thr-X-X-Glu/Asp/SerP/TyrP). In particular, the failure to recognize Asp as crucial specificity determinant prevents the phosphorylation of the specific CK2 peptide substrate RRRADDSDDDDD by GEF-CK. Thus, peptide substrates are now available for the fast and specific monitoring of all the three classes of 'casein kinases', CK1, CK2 and GEF-CK.
Lasa-Benito
M
M
Dipartimento di Chimica Biologica, Università di Padova, Italy.
Marin
O
O
Meggio
F
F
Pinna
L A
LA
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D047390:Casein Kinase II; D047388:Casein Kinases; D002364:Caseins / Q000378:metabolism*; D016384:Consensus Sequence; D005260:Female; D006056:Golgi Apparatus / Q000201:enzymology*; D007700:Kinetics; D008321:Mammary Glands, Animal / Q000201:enzymology*; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D051381:Rats; D013379:Substrate Specificity
D000596:Amino Acids; D002364:Caseins; D010455:Peptides; D011494:Protein Kinases; D047390:Casein Kinase II; D047388:Casein Kinases; D017346:Protein Serine-Threonine Kinases