SECRETORY SALIVARY PROTEIN SPECIFIC PROTEIN KINASES

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The overall objective of this study is to characterize the protein kinases present in the major salivary glands which phosphorylate secreted salivary proteins. The phosphorylated forms of the salivary substrates, acidic proline-rich proteins, statherin, and histatin 1, in particular, are important in the maintenance of the acquired enamel pellicle and tooth integrity. Kinase activity will be assayed with various peptide substrates based upon the sequences surrounding the phosphoserines in the acidic proline-rich proteins, statherin, and histatin 1. These activities will be purified from the parotid gland of Macaca fascicularis by sequential chromatographic techniques. The substrate specificity, nucleotide requirement, metal requirement, and pH dependence will be determined for each purified kinase. In addition, the amino-terminal sequence of each kinase will be determined. These sequences will be used to develop oligonucleotide probes, which in addition to antibodies, will be used to screen a cDNA expression library from a macaque parotid gland. The complete primary structure will be determined by progressive oligonucleotide sequencing. The sequences will be compared to those in existing sequence databases. In addition, the existence of the two consensus sequences for known serine/threonine kinases will be determined. Sequence information from both amino acid and oligonucleotide sequencing studies will be used for analysis of protein sequences in established databases. Such studies will be necessary for understanding the regulation and coordination of the synthesis, phosphorylation, and secretion of irreversibly phosphorylated proteins such as the salivary phosphoproteins, phosvitins, and phosphophoryns.