What question did this study set out to answer?

To determine whether protein kinase C-mediated down-regulation of Na,K-ATPase depends on direct pump phosphorylation or changes in cell surface membrane area.

March 1, 1997Molecular Biology of the CellOpen Access

Phorbol 12-myristate 13-acetate down-regulates Na,K-ATPase independent of its protein kinase C site: decrease in basolateral cell surface area.

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Authors

JBJ BeronActelion (Switzerland)IFIan C. ForsterFlorey Institute of Neuroscience and Mental Health PBPascal BéguinAgency for Science, Technology and Research

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Implication

Experimental study demonstrates that PMA down-regulates Na,K-ATPase by reducing basolateral surface area in A6 epithelia, suggesting pump removal occurs independently of direct phosphorylation.

Key Points

To determine whether protein kinase C-mediated down-regulation of Na,K-ATPase depends on direct pump phosphorylation or changes in cell surface membrane area.
Measured Na,K-ATPase pump currents in amphotericin B-permeabilized A6 epithelia expressing wild-type or PKC phosphorylation mutant (T15A/S16A) alpha 1 subunits following PMA exposure with or without the PKC inhibitor BIM (GF 109203X).
Assessed surface pump density, fluid phase endocytosis, and basolateral membrane area using ouabain binding, cell surface biotinylation, and transepithelial capacitance measurements.
PMA decreased Na,K-ATPase pump current by approximately 30% within 25 min (peaking after 40 min) independent of intracellular sodium and PKC phosphorylation sites, an effect blocked by BIM.
A distinct BIM-resistant, PKC site-independent current reduction of approximately 50% occurred when measured at low (5 mM) sodium concentrations.
PMA stimulation reduced surface Na,K-ATPase by 14% to 20% within 25 min, stimulated fluid phase endocytosis sevenfold, and reduced basolateral cell surface area by 16.5%.

Cite This Study

Beron et al. (1997) studied this question.

synapsesocial.com/papers/6a87c4b3f8efd6d7e4fb110e https://doi.org/10.1091/mbc.8.3.387

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Implication

Experimental study demonstrates that PMA down-regulates Na,K-ATPase by reducing basolateral surface area in A6 epithelia, suggesting pump removal occurs independently of direct phosphorylation.

Phorbol 12-myristate 13-acetate down-regulates Na,K-ATPase independent of its protein kinase C site: decrease in basolateral cell surface area.

Discussion

Member takes

Implication

Key Points

Cite This Study

Phorbol 12-myristate 13-acetate down-regulates Na,K-ATPase independent of its protein kinase C site: decrease in basolateral cell surface area.

Discussion

Member takes

Implication

Key Points

Cite This Study

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