Regulation of Epithelial Na + Permeability by Protein Kinase C is Tissue Specific

1996 ◽  
Vol 152 (3) ◽  
pp. 207-215 ◽  
Author(s):  
M.L. Chalfant ◽  
J.M. Civan ◽  
K. Peterson-Yantorno ◽  
D.R. DiBona ◽  
T.G. O'Brien
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Tissue Specific ◽  
Kinase C ◽  
Na Permeability

Effects of luminal Na+ on single Na+ channels in A6 cells, a regulatory role for protein kinase C

1989 ◽  
Vol 256 (6) ◽  
pp. F1094-F1103 ◽  
Author(s):  
B. N. Ling ◽  
D. C. Eaton
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Calcium Ionophore ◽  
Direct Interaction ◽  
Na Channel ◽  
Na Channels ◽  
Channel Activity ◽  
Pipette Solution ◽  
Kinase C ◽  
Na Permeability

Na+ "self-inhibition" in tight epithelia describes the reduction in apical Na+ permeability observed with increasing luminal Na+ concentration. Patch clamp was used to examine regulation of self-inhibition at the level of single Na+ channels. After cell-attached patches (pipette solution, 129 mM NaCl) were obtained on amphibian distal nephron cells (A6), the 129 mM NaCl (high Na+) apical bath outside of the patch was replaced with 3 mM NaCl (low Na+). Within minutes there was an increase in open channel probability (Po) and the appearance of one to five "new" channels in patch membranes. A similar increase occurred when apical Na+ entry was blocked by luminal amiloride (10 microM). A23187 (1 microM), a calcium ionophore, added after low Na+ exchange, abolished the rise in channel activity. Increased Po and new channels, induced by either luminal Na+ or amiloride, were also reversed by either 4B-phorbol 12-myristate 13-acetate (PMA; 0.1 microM) or 1-oleyl-2-acetyl glycerol (OAG; 10 microM) over 15-30 min. 4 alpha-Phorbol (0.1 microM), an inactive phorbol, did not reduce channel activity. D-Sphingosine (100 microM), a protein kinase C (PKC) inhibitor, increased Po and new channels. Conclusions: 1) modulation of apical Na+ permeability by luminal Na+ does not require direct interaction of Na+ with the channel protein but, rather, appears to involve an intracellular regulatory pathway, 2) relieving self-inhibition alters both the number and kinetics of single Na+ channels, 3) the effect of low Na+ must be modulated via decreased apical Na+ entry and intracellular Na+, since amiloride yielded similar results, 4) changes in intracellular Na+ probably affect Na+ channel activity via cytosolic Ca2+, 5) the effects of decreasing luminal Na+ are reversed by PKC activators and mimicked by PKC inhibitors suggesting a possible role for PKC in Na+ self-inhibition.

TISSUE-SPECIFIC PROTEIN KINASE C ISOFORMS DIFFERENTIALLY MEDIATE MACROPHAGE TNFα AND IL-1β PRODUCTION

Shock ◽  
1998 ◽  
Vol 9 (4) ◽  
pp. 256-260 ◽  
Author(s):  
Daniel R. Meldrum ◽  
Xianzhong Meng ◽  
Brett C. Sheridan ◽  
Robert C. McIntyre ◽  
Alden H. Harken ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Specific Protein ◽  
Tissue Specific ◽  
Kinase C ◽  
Protein Kinase C Isoforms ◽  
Specific Protein Kinase

scholarly journals Protein kinase C in the wood frog, Rana sylvatica: reassessing the tissue-specific regulation of PKC isozymes during freezing

2014 ◽  
Author(s):  
Christopher A. Dieni ◽  
Kenneth B. Storey
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Second Messengers ◽  
Rana Sylvatica ◽  
Wood Frog ◽  
Whole Body ◽  
Phosphorylation Sites ◽  
Tissue Specific ◽  
Kinase C ◽  
Pkc Isozymes

The wood frog, Rana sylvatica, survives whole-body freezing and thawing each winter. The extensive adaptations required at the biochemical level are facilitated by alterations to signaling pathways, including the insulin/Akt and AMPK pathways. Past studies investigating changing tissue-specific patterns of the second messenger IP3 in adapted frogs have suggested important roles for protein kinase C (PKC) in response to stress. In addition to their dependence on second messengers, phosphorylation of three PKC sites by upstream kinases (most notably PDK1) is needed for full PKC activation, according to current generally-accepted models. The present study uses phospho-specific immunoblotting to investigate phosphorylation states of PKC- as they relate to distinct tissues, PKC isozymes, and phosphorylation sites- in control and frozen frogs. In contrast to past studies where second messengers of PKC increased during the freezing process, phosphorylation of PKC tended to generally decline in most tissues of frozen frogs. All PKC isozymes and specific phosphorylation sites detected by immunoblotting decreased in phosphorylation levels in hind leg skeletal muscle and hearts of frozen frogs. Most PKC isozymes and specific phosphorylation sites detected in livers and kidneys also declined; the only exceptions were the levels of isozymes/phosphorylation sites detected by the phospho-PKCα/βII (Thr638/641) antibody, which remained unchanged from control to frozen frogs. Changes in brains of frozen frogs were unique; no decreases were observed in the phosphorylation levels of any of the PKC isozymes and/or specific phosphorylation sites detected by immunoblotting. Rather, increases were observed for the levels of isozymes/phosphorylation sites detected by the phospho-PKCα/βII (Thr638/641), phospho-PKCδ (Thr505), and phospho-PKCθ (Thr538) antibodies; all other isozymes/phosphorylation sites detected in brain remained unchanged from control to frozen frogs. The results of this study indicate a potential important role for PKC in cerebral protection during wood frog freezing. Our findings also call for a reassessment of the previously-inferred importance of PKC in other tissues, particularly in liver; a more thorough investigation is required to determine whether PKC activity in this physiological situation is indeed dependent on phosphorylation, or whether it deviates from the generally-accepted model and can be “overridden” by exceedingly high levels of second messengers, as has been demonstrated with certain PKC isozymes (e.g. PKCδ).

Tissue-specific expression of three distinct types of rabbit protein kinase C

Nature ◽  
1987 ◽  
Vol 325 (6100) ◽  
pp. 161-166 ◽  
Author(s):  
Shigeo Ohno ◽  
Hiroshi Kawasaki ◽  
Shinobu Imajoh ◽  
Koichi Suzuki ◽  
Masaki Inagaki ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Specific Expression ◽  
Tissue Specific ◽  
Tissue Specific Expression ◽  
Kinase C
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