scholarly journals Effect of experimental diabetes and glucagon on cAMP-dependent protein kinase in rat liver

Diabetologia ◽  
1977 ◽  
Vol 13 (2) ◽  
pp. 153-157 ◽  
Author(s):  
H. E. Weber ◽  
L. A. Menahan ◽  
S. N. Chaudhuri ◽  
J. C. Shipp
Keyword(s):  
Protein Kinase ◽  
Rat Liver ◽  
Experimental Diabetes ◽  
Dependent Protein Kinase ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein

scholarly journals cAMP-dependent protein kinase phosphorylates and activates nuclear Ca2+-ATPase

1998 ◽  
Vol 95 (16) ◽  
pp. 9178-9183 ◽  
Author(s):  
Patrick J. Rogue ◽  
Jean-Paul Humbert ◽  
Alphonse Meyer ◽  
Solange Freyermuth ◽  
Marie-Marthe Krady ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nuclear Envelope ◽  
Rat Liver ◽  
Protein Band ◽  
Partial Purification ◽  
Dependent Protein Kinase ◽  
Rat Liver Nuclei ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Liver Nuclei

A Ca2+-pump ATPase, similar to that in the endoplasmic reticulum, has been located on the outer membrane of rat liver nuclei. The effect of cAMP-dependent protein kinase (PKA) on nuclear Ca2+-ATPase (NCA) was studied by using purified rat liver nuclei. Treatment of isolated nuclei with the catalytic unit of PKA resulted in the phosphorylation of a 105-kDa band that was recognized by antibodies specific for sarcoplasmic reticulum Ca2+-ATPase type 2b. Partial purification and immunoblotting confirmed that the 105-kDa protein band phosphorylated by PKA is NCA. The stoichiometry of phosphorylation was 0.76 mol of phosphate incorporated/mol of partially purified enzyme. Measurement of ATP-dependent 45Ca2+ uptake into purified nuclei showed that PKA phosphorylation enhanced the Ca2+-pumping activity of NCA. We show that PKA phosphorylation of Ca2+-ATPase enhances the transport of 10-kDa fluorescent-labeled dextrans across the nuclear envelope. The findings reported in this paper are consistent with the notion that the crosstalk between the cAMP/PKA- and Ca2+-dependent signaling pathways identified at the cytoplasmic level extends to the nucleus. Furthermore, these data support a function for crosstalk in the regulation of calcium-dependent transport across the nuclear envelope.

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