Inhibition of Myosin Light Chain Kinase, cAMP-Dependent Protein Kinase, Protein Kinase C and of Plant Ca2⊕-Dependent Protein Kinase by Anthraquinones

1992 ◽  
Vol 373 (2) ◽  
pp. 903-910 ◽  
Author(s):  
Wanida JINSART ◽  
Bela TERNAI ◽  
Gideon M. POLYA
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Kinase C ◽  
Dependent Protein

scholarly journals Regulation of actin microfilament integrity in living nonmuscle cells by the cAMP-dependent protein kinase and the myosin light chain kinase.

1988 ◽  
Vol 106 (6) ◽  
pp. 1955-1971 ◽  
Author(s):  
N J Lamb ◽  
A Fernandez ◽  
M A Conti ◽  
R Adelstein ◽  
D B Glass ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Complete Loss ◽  
Dependent Protein Kinase ◽  
Actin Microfilament ◽  
Camp Dependent Protein Kinase ◽  
Nonmuscle Cells ◽  
Dependent Protein

Microinjection of the catalytic subunit of cAMP-dependent protein kinase (A-kinase) into living fibroblasts or the treatment of these cells with agents that elevate the intracellular cAMP level caused marked alterations in cell morphology including a rounded phenotype and a complete loss of actin microfilament bundles. These effects were transient and fully reversible. Two-dimensional gel electrophoresis was used to analyze the changes in phosphoproteins from cells injected with A-kinase. These experiments showed that accompanying the disassembly of actin microfilaments, phosphorylation of myosin light chain kinase (MLCK) increased and concomitantly, the phosphorylation of myosin P-light chain decreased. Moreover, inhibiting MLCK activity via microinjection of affinity-purified antibodies specific to native MLCK caused a complete loss of microfilament bundle integrity and a decrease in myosin P-light chain phosphorylation, similar to that seen after injection of A-kinase. These data support the idea that A-kinase may regulate microfilament integrity through the phosphorylation and inhibition of MLCK activity in nonmuscle cells.

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