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Updated: Jul 28, 2026

Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
15:43

Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes

Published on: January 7, 2013

Proline transport in MDCK cells expressing a mutant regulatory subunit of cAMP-dependent protein kinase

I Zelikovic1, J Wager-Miller

  • 1Department of Pediatrics, Division of Nephrology, University of Washington School of Medicine, 4800 Sand Point Way NW, Seattle, Washington 98105, USA. i_zelikovic@rambam.health.gov.il

Molecular Genetics and Metabolism
|February 13, 2001
PubMed

Insights

cAMP-dependent protein kinase (cAK) regulates proline transport in kidney cells. Expressing a mutant cAK subunit reversed cAMP-mediated inhibition, suggesting cAK controls amino acid transport in the renal tubule.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Renal Physiology

Background:

  • cAMP-dependent protein kinase (cAK) is known to regulate ion channels and carriers.
  • The specific role of cAK in osmoprotective amino acid transport within the renal distal tubule remains uncharacterized.

Purpose of the Study:

  • To investigate the regulatory role of cAK in Na(+)- and Cl(-)-dependent proline transport.
  • To determine if cAK mediates the effects of cAMP on proline transport in renal cells.

Main Methods:

  • MDCK cells were transfected with a mutant murine regulatory subunit (RIalpha(AB)) of cAK.
  • Stable cell lines expressing the mutant subunit (M(AB)) or a control (M(neo)) were established.
  • Proline uptake was measured in response to cAMP-stimulating agents (forskolin and IBMX).

Main Results:

  • Elevated cAMP levels significantly inhibited proline transport in control M(neo) cells (48-45% inhibition).
  • In contrast, proline transport in M(AB) cells expressing the mutant cAK subunit showed minimal inhibition (9% at 5 min, 0% at 15 min).
  • These findings indicate that the mutant cAK subunit prevents cAMP-induced inhibition of proline transport.

Conclusions:

  • cAK plays a crucial role in mediating the modulatory effects of cAMP on proline transport.
  • The data suggest that cAK is involved in regulating the transport of proline and other osmoprotective amino acids in the renal tubule.

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