scholarly journals The α Isoform of Protein Kinase C Is Involved in Signaling the Response of Desmosomes to Wounding in Cultured Epithelial Cells

2000 ◽  
Vol 11 (3) ◽  
pp. 1077-1092 ◽  
Author(s):  
Sarah Wallis ◽  
Susan Lloyd ◽  
Irene Wise ◽  
Grenham Ireland ◽  
Tom P. Fleming ◽  
...  

Initiation of reepithelialization upon wounding is still poorly understood. To enhance this understanding, we focus here on changes in the adhesive state of desmosomes of cultured Madin-Darby canine kidney cells in response to wounding of confluent cell sheets. Previous results show that desmosomal adhesion in Madin-Darby canine kidney cells changes from a calcium-dependent state to calcium independence in confluent cell sheets. We show that this change, which requires culture confluence to develop, is rapidly reversed upon wounding of confluent cell sheets. Moreover, the change to calcium dependence in wound edge cells is propagated to cells hundreds of micrometers away from the wound edge. Rapid transition from calcium independence to calcium dependence also occurs when cells are treated with phorbol esters that activate PKC. PKC inhibitors, including the conventional isoform inhibitor Gö6976, cause rapid transition from calcium dependence to calcium independence, even in subconfluent cells. The cellular location of the α isoform of PKC correlates with the calcium dependence of desmosomes. Upon monolayer wounding, PKCα translocates rapidly to the cell periphery, becomes Triton X-100 insoluble, and also becomes concentrated in lamellipodia. The PKCα translocation upon wounding precedes both the increase in PKC activity in the membrane fraction and the reversion of desmosomes to calcium dependence. Specific depletion of PKCα with an antisense oligonucleotide increases the number of cells with calcium-independent desmosomes. These results show that PKCα participates in a novel signaling pathway that modulates desmosomal adhesion in response to wounding.

1991 ◽  
Vol 266 (27) ◽  
pp. 17729-17732 ◽  
Author(s):  
S.H. Low ◽  
S.H. Wong ◽  
B.L. Tang ◽  
P. Tan ◽  
V.N. Subramaniam ◽  
...  

2019 ◽  
Vol 317 (1) ◽  
pp. F30-F42
Author(s):  
Te-Jung Lu ◽  
Wei-Chih Kan ◽  
Sung-Sen Yang ◽  
Si-Tse Jiang ◽  
Sheng-Nan Wu ◽  
...  

Liddle syndrome is an inherited form of human hypertension caused by increasing epithelial Na+ channel (ENaC) expression. Increased Na+ retention through ENaC with subsequent volume expansion causes hypertension. In addition to ENaC, the Na+-K+-Cl− cotransporter (NKCC) and Na+-Cl− symporter (NCC) are responsible for Na+ reabsorption in the kidneys. Several Na+ transporters are evolutionarily regulated by the Ste20 kinase family. Ste20-related proline/alanine-rich kinase and oxidative stress-responsive kinase-1 phosphorylate downstream NKCC2 and NCC to maintain Na+ and blood pressure (BP) homeostasis. Mammalian Ste20 kinase 3 (MST3) is another member of the Ste20 family. We previously reported that reduced MST3 levels were found in the kidneys in spontaneously hypertensive rats and that MST3 was involved in Na+ regulation. To determine whether MST3 is involved in BP stability through Na+ regulation, we generated a MST3 hypomorphic mutation and designated MST3+/− and MST3−/− mice to examine BP and serum Na+ and K+ concentrations. MST3−/− mice exhibited hypernatremia, hypokalemia, and hypertension. The increased ENaC in the kidney played roles in hypernatremia. The reabsorption of more Na+ promoted more K+ secretion in the kidney and caused hypokalemia. The hypernatremia and hypokalemia in MST3−/− mice were significantly reversed by the ENaC inhibitor amiloride, indicating that MST3−/− mice reabsorbed more Na+ through ENaC. Furthermore, Madin-Darby canine kidney cells stably expressing kinase-dead MST3 displayed elevated ENaC currents. Both the in vivo and in vitro results indicated that MST3 maintained Na+ homeostasis through ENaC regulation. We are the first to report that MST3 maintains BP stability through ENaC regulation.


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