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Mol Med. 1998 April; 4(4): 258–265.
PMCID: PMC2230359

Na+,K(+)-ATPase phosphorylation in the choroid plexus: synergistic regulation by serotonin/protein kinase C and isoproterenol/cAMP-PK/PP-1 pathways.

Abstract

BACKGROUND: The ion pump Na+,K(+)-ATPase is responsible for the secretion of cerebrospinal fluid from the choroid plexus. In this tissue, the activity of Na+,K(+)-ATPase is inhibited by serotonin via stimulation of protein kinase C-catalyzed phosphorylation. The choroid plexus is highly enriched in two phosphoproteins which act as regulators of protein phosphatase-1 activity, DARPP-32 and inhibitor-1. Phosphorylation catalyzed by cAMP-dependent protein kinase on a single threonyl residue converts DARPP-32 and inhibitor-1 into potent inhibitors of protein phosphatase-1. Previous work has shown that in the choroid plexus, phosphorylation of DARPP-32 and I-1 is enhanced by isoproterenol and other agents that activate cAMP-PK. We have now examined the possible involvement of the cAMP-PK/protein phosphatase-1 pathway in the regulation of Na+,K(+)-ATPase. MATERIALS AND METHODS: The state of phosphorylation of Na+,K(+)-ATPase was measured by determining the amount of radioactivity incorporated into the ion pump following immunoprecipitation from 32P-prelabeled choroid plexuses incubated with various drugs (see below). Two-dimensional phosphopeptide mapping was employed to identify the protein kinase involved in the phosphorylation of Na+,K(+)-ATPase. RESULTS: The serotonin-mediated increase in Na+,K(+)-ATPase phosphorylation is potentiated by okadaic acid, an inhibitor of protein phosphatases-1 and -2A, as well as by forskolin or the beta-adrenergic agonist, isoproterenol, activators of cAMP-dependent protein kinase. Two-dimensional phosphopeptide maps suggest that this potentiating action occurs at the level of a protein kinase C phosphorylation site. Forskolin and isoproterenol also stimulate the phosphorylation of DARPP-32 and protein phosphatase inhibitor-1, which in their phosphorylated form are potent inhibitors of protein phosphatase-1. CONCLUSIONS: The results presented here support a model in which okadaic acid, forskolin, and isoproterenol achieve their synergistic effects with serotonin through phosphorylation of DARPP-32 and inhibitor-1, inhibition of protein phosphatase-1, and a reduction of dephosphorylation of Na+,K(+)-ATPase at a protein kinase C phosphorylation site.

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Selected References

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  • Pollay M, Hisey B, Reynolds E, Tomkins P, Stevens FA, Smith R. Choroid plexus Na+/K+-activated adenosine triphosphatase and cerebrospinal fluid formation. Neurosurgery. 1985 Nov;17(5):768–772. [PubMed]
  • Lindvall M, Edvinsson L, Owman C. Sympathetic nervous control of cerebrospinal fluid production from the choroid plexus. Science. 1978 Jul 14;201(4351):176–178. [PubMed]
  • Steardo L, Nathanson JA. Brain barrier tissues: end organs for atriopeptins. Science. 1987 Jan 23;235(4787):470–473. [PubMed]
  • Lindvall-Axelsson M, Mathew C, Nilsson C, Owman C. Effect of 5-hydroxytryptamine on the rate of cerebrospinal fluid production in rabbit. Exp Neurol. 1988 Feb;99(2):362–368. [PubMed]
  • Bertorello AM, Aperia A, Walaas SI, Nairn AC, Greengard P. Phosphorylation of the catalytic subunit of Na+,K(+)-ATPase inhibits the activity of the enzyme. Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11359–11362. [PubMed]
  • Fisone G, Snyder GL, Fryckstedt J, Caplan MJ, Aperia A, Greengard P. Na+,K(+)-ATPase in the choroid plexus. Regulation by serotonin/protein kinase C pathway. J Biol Chem. 1995 Feb 10;270(6):2427–2430. [PubMed]
  • Li D, Aperia A, Celsi G, da Cruz e Silva EF, Greengard P, Meister B. Protein phosphatase-1 in the kidney: evidence for a role in the regulation of medullary Na(+)-K(+)-ATPase. Am J Physiol. 1995 Nov;269(5 Pt 2):F673–F680. [PubMed]
  • Hemmings HC, Jr, Girault JA, Nairn AC, Bertuzzi G, Greengard P. Distribution of protein phosphatase inhibitor-1 in brain and peripheral tissues of various species: comparison with DARPP-32. J Neurochem. 1992 Sep;59(3):1053–1061. [PubMed]
  • Hemmings HC, Jr, Greengard P, Tung HY, Cohen P. DARPP-32, a dopamine-regulated neuronal phosphoprotein, is a potent inhibitor of protein phosphatase-1. Nature. 1984 Aug 9;310(5977):503–505. [PubMed]
  • Snyder GL, Girault JA, Chen JY, Czernik AJ, Kebabian JW, Nathanson JA, Greengard P. Phosphorylation of DARPP-32 and protein phosphatase inhibitor-1 in rat choroid plexus: regulation by factors other than dopamine. J Neurosci. 1992 Aug;12(8):3071–3083. [PubMed]
  • Pietrini G, Matteoli M, Banker G, Caplan MJ. Isoforms of the Na,K-ATPase are present in both axons and dendrites of hippocampal neurons in culture. Proc Natl Acad Sci U S A. 1992 Sep 15;89(18):8414–8418. [PubMed]
  • Zlokovic BV, Mackic JB, Wang L, McComb JG, McDonough A. Differential expression of Na,K-ATPase alpha and beta subunit isoforms at the blood-brain barrier and the choroid plexus. J Biol Chem. 1993 Apr 15;268(11):8019–8025. [PubMed]
  • Laemmli UK. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. [PubMed]
  • Fisone G, Cheng SX, Nairn AC, Czernik AJ, Hemmings HC, Jr, Hög JO, Bertorello AM, Kaiser R, Bergman T, Jörnvall H, et al. Identification of the phosphorylation site for cAMP-dependent protein kinase on Na+,K(+)-ATPase and effects of site-directed mutagenesis. J Biol Chem. 1994 Mar 25;269(12):9368–9373. [PubMed]
  • Nathanson JA. Beta-adrenergic-sensitive adenylate cyclase in secretory cells of choroid plexus. Science. 1979 May 25;204(4395):843–844. [PubMed]
  • Lindvall M, Gustafson A, Hedner P, Owman C. Stimulation of cyclic adenosine 3',5'-monophosphate formation in rabbit choroid plexus by beta-receptor agonists and vasoactive intestinal polypeptide. Neurosci Lett. 1985 Mar 15;54(2-3):153–157. [PubMed]
  • Beguin P, Beggah AT, Chibalin AV, Burgener-Kairuz P, Jaisser F, Mathews PM, Rossier BC, Cotecchia S, Geering K. Phosphorylation of the Na,K-ATPase alpha-subunit by protein kinase A and C in vitro and in intact cells. Identification of a novel motif for PKC-mediated phosphorylation. J Biol Chem. 1994 Sep 30;269(39):24437–24445. [PubMed]
  • Feschenko MS, Sweadner KJ. Structural basis for species-specific differences in the phosphorylation of Na,K-ATPase by protein kinase C. J Biol Chem. 1995 Jun 9;270(23):14072–14077. [PubMed]
  • Middleton JP, Khan WA, Collinsworth G, Hannun YA, Medford RM. Heterogeneity of protein kinase C-mediated rapid regulation of Na/K-ATPase in kidney epithelial cells. J Biol Chem. 1993 Jul 25;268(21):15958–15964. [PubMed]
  • Boyson SJ, Alexander A. Net production of cerebrospinal fluid is decreased by SCH-23390. Ann Neurol. 1990 Jun;27(6):631–635. [PubMed]
  • Haywood JR, Vogh BP. Some measurements of autonomic nervous system influence on production of cerebrospinal fluid in the cat. J Pharmacol Exp Ther. 1979 Feb;208(2):341–346. [PubMed]
  • Lindvall M, Edvinsson L, Owman C. Effect of sympathomimetic drugs and corresponding receptor antagonists on the rate of cerebrospinal fluid production. Exp Neurol. 1979 Apr;64(1):132–145. [PubMed]

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