title: Phosphorylation of the salivary Na(+)-K(+)-2Cl(-) cotransporter.
abstract: We studied the phosphorylation of the secretory Na(+)-K(+)-2Cl(-) cotransporter (NKCC1) in rat parotid acinar cells. We have previously shown that NKCC1 activity in these cells is dramatically upregulated in response to beta-adrenergic stimulation and that this upregulation correlates with NKCC1 phosphorylation, possibly due to protein kinase A (PKA). We show here that when ATP is added to purified acinar basolateral membranes (BLM), NKCC1 is phosphorylated as a result of membrane-associated protein kinase activity. Additional NKCC1 phosphorylation is seen when PKA is added to BLMs, but our data indicate that this is due to an effect of PKA on endogenous membrane kinase or phosphatase activities, rather than its direct phosphorylation of NKCC1. Also, phosphopeptide mapping demonstrates that these phosphorylations do not take place at the site associated with the upregulation of NKCC1 by beta-adrenergic stimulation. However, this upregulatory phosphorylation can be mimicked by the addition of cAMP to permeabilized acini, and this effect can be blocked by a specific PKA inhibitor. These latter results provide good evidence that PKA is indeed involved in the upregulatory phosphorylation of NKCC1 and suggest that an additional factor present in the acinar cell but absent from isolated membranes is required to bring about the phosphorylation.
authors.affiliation: Department of Oral Physiology, School of Dentistry, Meikai University, Sakada-shi, Saitama 350-0283, Japan.
authors.forename: Kinji
authors.initials: K
authors.lastname: Kurihara
authors.forename: Nobuo
authors.initials: N
authors.lastname: Nakanishi
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Moore-Hoon
authors.forename: R James
authors.initials: RJ
authors.lastname: Turner
mesh_terms: D000255:Adenosine Triphosphate / Q000493:pharmacokinetics; D000818:Animals; D002227:Carbazoles / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D026121:Indole Alkaloids; D007211:Indoles / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D008387:Marine Toxins; D052998:Microcystins; D019319:Okadaic Acid / Q000494:pharmacology; D010080:Oxazoles / Q000494:pharmacology; D010306:Parotid Gland / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000494:pharmacology; D010636:Phenols / Q000494:pharmacology; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D051381:Rats; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism*; D064506:Solute Carrier Family 12, Member 2; D019311:Staurosporine / Q000494:pharmacology; D013449:Sulfonamides; D013566:Sympathomimetics / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology
chemical_list: D002227:Carbazoles; D026121:Indole Alkaloids; D007211:Indoles; D007546:Isoquinolines; D008301:Maleimides; D008387:Marine Toxins; D052998:Microcystins; D010080:Oxazoles; D010456:Peptides, Cyclic; D010636:Phenols; D010761:Phosphorus Radioisotopes; C578879:Slc12a2 protein, rat; D028021:Sodium-Potassium-Chloride Symporters; D064506:Solute Carrier Family 12, Member 2; D013449:Sulfonamides; D013566:Sympathomimetics; D019319:Okadaic Acid; D014638:Vanadates; C062898:lavendustin A; C059041:calyculin A; D000255:Adenosine Triphosphate; C049985:staurosporine aglycone; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; C057862:cyanoginosin LR; D019311:Staurosporine; D007545:Isoproterenol; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C088060:bisindolylmaleimide