Insulin increases plasma membrane content and reduces phosphorylation of Na +-K + pump α 1-subunit in HEK-293 cells

Gary Sweeney, Wenyan Niu, Victor Canfield, Robert Levenson, Amira Klip

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Insulin stimulates K + uptake and Na + efflux via the Na +-K + pump in kidney, skeletal muscle, and brain. The mechanism of insulin action in these tissues differs, in part, because of differences in the isoform complement of the catalytic α-subunit of the Na +-K + pump. To analyze specifically the effect of insulin on the α 1-isoform of the pump, we have studied human embryonic kidney (HEK)-293 cells stably transfected with the rat Na +-K + pump α 1-isoform tagged on its first exofacial loop with a hemagglutinin (HA) epitope. The plasma membrane content of α 1-subunits was quantitated by binding a specific HA antibody to intact cells. Insulin rapidly increased the number of α 1-subunits at the cell surface. This gain was sensitive to the phosphatidylinositol (PI) 3-kinase inhibitor wortmannin and to the protein kinase C (PKC) inhibitor bisindolylmaleimide. Furthermore, the insulin-stimulated gain in surface α 1-subunits correlated with an increase in the binding of an antibody that recognizes only the nonphosphorylated form of α 1 (at serine-18). These results suggest that insulin regulates the Na +-K + pump in HEK-293 cells, at least in part, by decreasing serine phosphorylation and increasing plasma membrane content of α 1-subunits via a signaling pathway involving PI 3-kinase and PKC.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume281
Issue number6 50-6
StatePublished - Dec 1 2001

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Phosphorylation
Cell Membrane
Insulin
Kidney
Phosphatidylinositol 3-Kinase
Protein Isoforms
Hemagglutinins
Serine
Protein Kinase C
Antibodies
Protein C Inhibitor
Protein Kinase Inhibitors
Epitopes
Catalytic Domain
Skeletal Muscle
Brain

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cell Biology

Cite this

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title = "Insulin increases plasma membrane content and reduces phosphorylation of Na +-K + pump α 1-subunit in HEK-293 cells",
abstract = "Insulin stimulates K + uptake and Na + efflux via the Na +-K + pump in kidney, skeletal muscle, and brain. The mechanism of insulin action in these tissues differs, in part, because of differences in the isoform complement of the catalytic α-subunit of the Na +-K + pump. To analyze specifically the effect of insulin on the α 1-isoform of the pump, we have studied human embryonic kidney (HEK)-293 cells stably transfected with the rat Na +-K + pump α 1-isoform tagged on its first exofacial loop with a hemagglutinin (HA) epitope. The plasma membrane content of α 1-subunits was quantitated by binding a specific HA antibody to intact cells. Insulin rapidly increased the number of α 1-subunits at the cell surface. This gain was sensitive to the phosphatidylinositol (PI) 3-kinase inhibitor wortmannin and to the protein kinase C (PKC) inhibitor bisindolylmaleimide. Furthermore, the insulin-stimulated gain in surface α 1-subunits correlated with an increase in the binding of an antibody that recognizes only the nonphosphorylated form of α 1 (at serine-18). These results suggest that insulin regulates the Na +-K + pump in HEK-293 cells, at least in part, by decreasing serine phosphorylation and increasing plasma membrane content of α 1-subunits via a signaling pathway involving PI 3-kinase and PKC.",
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Insulin increases plasma membrane content and reduces phosphorylation of Na +-K + pump α 1-subunit in HEK-293 cells. / Sweeney, Gary; Niu, Wenyan; Canfield, Victor; Levenson, Robert; Klip, Amira.

In: American Journal of Physiology - Cell Physiology, Vol. 281, No. 6 50-6, 01.12.2001.

Research output: Contribution to journalArticle

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