scholarly journals Role of cell volume and protein kinase C in regulation of a Cl- conductance in single proximal tubule cells of Rana temporaria.

1994 ◽  
Vol 480 (1) ◽  
pp. 1-7 ◽  
Author(s):  
L Robson ◽  
M Hunter
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Proximal Tubule ◽  
Cell Volume ◽  
Rana Temporaria ◽  
Proximal Tubule Cells ◽  
Kinase C ◽  
Tubule Cells ◽  
Cl Conductance

Diacylglycerol activation of protein kinase C results in a dual effect on Na+,K(+)-ATPase activity from intact renal proximal tubule cells

1992 ◽  
Vol 101 (2) ◽  
pp. 343-347
Author(s):  
A.M. Bertorello
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Atpase Activity ◽  
Proximal Tubule ◽  
Amphotericin B ◽  
Dual Effect ◽  
Proximal Tubule Cells ◽  
Kinase C ◽  
Tubule Cells ◽  
Renal Proximal Tubule Cells

This study evaluated the effect of L-1-oleoyl-2-acetyl-sn-3-glycerol (OAG) on ouabain-sensitive Na,K-dependent oxygen consumption (Na,K-QO2) in intact renal proximal tubule cells (RPTC). Basal Na,K-QO2 (nmol O2/mg protein per min) was 20.0 +/− 1.0. Incubation with 10 nM of OAG induced a dual effect on Na,K-QO2, with an initial stimulation (maximal at 10 min, 37.1 +/− 5.0), followed by an inhibition (significant at 20 min, 16.3 +/− 1.0). No changes in ouabain-insensitive QO2 were observed in any of the protocols. The effects were abolished by sphingosine, a protein kinase C inhibitor. Stimulation was abolished by amiloride 0.1 mM. Amiloride had no effect on Na,K-QO2 at the concentration used. Stimulation was not potentiated by the sodium ionophore, amphotericin B, and the later inhibition was still observed in the presence of amphotericin B. The initial stimulation was attributed to an increase in sodium permeability, while the later inhibition was attributed to a direct effect on the Na,K-pump. Regulation of Na+,K(+)-ATPase activity by protein kinase C in intact RPTC can be accomplished by a direct effect on the protein or as a secondary effect consequent upon changes in intracellular sodium.

Na+-alanine uptake activates a Cl− conductance in frog renal proximal tubule cells via nonconventional PKC

2001 ◽  
Vol 280 (5) ◽  
pp. F758-F767
Author(s):  
I. D. Millar ◽  
L. Robson
Keyword(s):  
Proximal Tubule ◽  
Atp Hydrolysis ◽  
Renal Proximal Tubule ◽  
Selectivity Ratio ◽  
Proximal Tubule Cells ◽  
Kinase C ◽  
Tubule Cells ◽  
Renal Proximal Tubule Cells ◽  
Pkc Activation ◽  
Cl Conductance

Hyposmotically induced swelling of frog renal proximal tubule cells activates a DIDS-sensitive, outwardly rectifying Cl−conductance via a conventional protein kinase C (PKC). This study examines whether Na+-alanine cotransport similarly activates a DIDS-sensitive Cl− conductance in frog renal proximal tubule cells. On stimulation of Na+-alanine cotransport, the DIDS-sensitive current ( I DIDS-Ala) increased markedly over time. I DIDS-Ala exhibited outward rectification, a Na+/Cl− selectivity ratio of 0.19 ± 0.03, and an anion selectivity sequence Br− = Cl− > I− > gluconate−. Activation of I DIDS-Alawas dependent on ATP hydrolysis and PKC-mediated phosphorylation and was inhibited by hyperosmotic conditions. Activation could be not ascribed to a conventional PKC isoform, as I DIDS-Ala was not affected by removing Ca2+ or by phorbol ester treatment, suggesting a role for a nonconventional PKC isoform, either novel or atypical. We conclude that Na+-alanine cotransport activates a DIDS-sensitive Cl− conductance via a nonconventional PKC isoform. This contrasts with the hyposmotically activated Cl−conductance, which requires conventional PKC activation.

The Expression and Role of Protein Kinase C in Neonatal Cardiac Myocyte Attachment, Cell Volume, and Myofibril Formation Is Dependent on the Composition of the Extracellular Matrix

2005 ◽  
Vol 11 (3) ◽  
pp. 224-234 ◽  
Author(s):  
Tara A. Bullard ◽  
Thomas K. Borg ◽  
Robert L. Price
Keyword(s):  
Extracellular Matrix ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Volume ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Dynamic Component ◽  
Laminin 5 ◽  
Kinase C

The extracellular matrix (ECM) is a dynamic component of tissues that influences cellular phenotype and behavior. We sought to determine the role of specific ECM substrates in the regulation of protein kinase C (PKC) isozyme expression and function in cardiac myocyte attachment, cell volume, and myofibril formation. PKC isozyme expression was ECM substrate specific. Increasing concentrations of the PKC δ inhibitor rottlerin attenuated myocyte attachment to randomly organized collagen (1, 5, and 10 μM), laminin (5 and 10 μM), aligned collagen (5 and 10 μM), and fibronectin (10 μM). Rottlerin significantly decreased cell volume on laminin and randomly organized collagen, and inhibited myofibril formation on laminin. The PKC α inhibitor Gö 6976 inhibited attachment to randomly organized collagen at 6 nM but did not affect cell volume. The general PKC inhibitor Bisindolylmalemide I (10 and 30 μM) did not affect myocyte attachment; however, it significantly decreased cell volume on randomly organized collagen. Our data indicate that PKC isozymes are expressed and utilized by neonatal cardiac myocytes during attachment, cell growth, and myofibril formation. Specifically, it appears that PKC δ and/or its downstream effectors play an important role in the interaction between cardiac myocytes and laminin, providing further evidence that the ECM influences cardiac myocyte behavior.

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