Effects of Protein Kinase CK2, Extracellular Signal-regulated Kinase 2, and Protein Phosphatase 2A on a Phosphatidic Acid-preferring Phospholipase A1

• Published in: The Journal of biological chemistry 2001-07, Vol.276 (29), p.27698-27708
• Main Authors: Han, May H., Han, David K.M., Aebersold, Ruedi H., Glomset, John A.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Casein Kinase II; Chromatography, Gel; Macaca; Male; Mass Spectrometry; Mitogen-Activated Protein Kinase 1 - metabolism; Molecular Sequence Data; Phosphatidic Acids - metabolism; Phospholipases A - chemistry; Phospholipases A - metabolism; Phospholipases A1; Phosphoprotein Phosphatases - metabolism; Phosphorylation; Precipitin Tests; Protein Binding; Protein Phosphatase 2; Protein-Serine-Threonine Kinases - metabolism; Testis - enzymology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M101983200

A soluble, phosphatidic acid-preferring phospholipase A1, expressed in mature bovine testes but not in newborn calf testes, may contribute to the formation or function of sperm. Here we incubated a recombinant preparation of the phospholipase in vitro with several enzymes including protein kinase CK2 (CK2), extracellular signal-regulated kinase 2 (ERK2), and protein phosphatase 2A (PP2A) to identify effects that might be of regulatory importancein vivo. Major findings were that 1) CK2 phosphorylated the phospholipase on serines 93, 105, and 716; 2) ERK2 phosphorylated the enzyme on serine 730; 3) there was cross-antagonism between the reactions that phosphorylated serines 716 and 730; 4) PP2A selectively hydrolyzed phosphate groups that were esterified to serines 716 and 730; 5) CK2α formed a stable, MgATP/MgGTP-dependent complex with the phospholipase by a novel mechanism; and 6) the complex showed reduced phospholipase activity and resembled a complex identified in homogenates of macaque testis. These results provide the first available information about the effects of reactions of phosphorylation and dephosphorylation on the behavior of the phospholipase, shed light on properties of CK2α that may be required for the formation of complexes with its substrates, and raise the possibility that a complex containing CK2α and the phospholipase may play a special biological role in the testis.