Catalytic subunit of protein kinase A is an interacting partner of the inflammation-responsive transcription factor serum amyloid A-activating factor-1.
Serum amyloid A-activating factor-1 (SAF-1) is a zinc finger transcription factor that is activated by many mediators of inflammation including IL-1, IL-6, and bacterial LPS. However, the mechanism of activation is not fully understood. To identify possible activation partners for SAF-1, we used a yeast two-hybrid system that detected interaction between the catalytic subunit of cyclic AMP-dependent protein kinase (PKA-Calpha) and SAF-1. Immunofluorescence and combined immunoprecipitation-Western blot analyses revealed colocalization and interaction between SAF-1 and PKA-Calpha. In vivo evidence of SAF-1 and PKA-Calpha interaction was further revealed by coimmunoprecipitation of these two proteins in cAMP-activated liver cells. We further show that SAF-1 is phosphorylated in vitro by PKA-Calpha and that addition of cAMP markedly induces in vivo phosphorylation of SAF-1 and transcription of SAF-regulated reporter genes. These results showed that SAF1-PKA-Calpha interaction is involved in functional activation of SAF-1.
Ray
B K
BK
Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
Chen
J
J
Ray
A
A
D000818:Animals; D020134:Catalytic Domain / Q000235:genetics; D002460:Cell Line; D000242:Cyclic AMP / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D007249:Inflammation / Q000201:enzymology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010766:Phosphorylation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000235:genetics; D000685:Serum Amyloid A Protein / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D015854:Up-Regulation
D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D000685:Serum Amyloid A Protein; D014157:Transcription Factors; C076035:c-MYC-associated zinc finger protein; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases