Fibroblast growth factor-2 binds to the regulatory beta subunit of CK2 and directly stimulates CK2 activity toward nucleolin.
The presence of fibroblast growth factor-2 (FGF-2) in the nucleus has now been reported both in vitro and in vivo, but its nuclear functions are unknown. Here, we show that FGF-2 added to nuclear extract binds to protein kinase CK2 and nucleolin, a CK2 natural substrate. Added to baculovirus-infected cell extracts overexpressing CK2 or its isolated subunits, FGF-2 binds to the enzyme through its regulatory beta subunit. Using purified proteins, FGF-2 is shown to directly interact with CK2 and to stimulate CK2 activity toward nucleolin. Furthermore, a mitogenic-deficient FGF-2 mutant protein has an impaired ability to interact with CK2 and to stimulate CK2 activity using nucleolin as substrate. We propose that in growing cells, one function of nuclear FGF-2 is to modulate CK2 activity through binding to its regulatory beta subunit.
Bonnet
H
H
Laboratoire de Biologie Moléculaire Eucaryote, CNRS, 118 route de Narbonne, 31062 Toulouse Cedex, France.
Filhol
O
O
Truchet
I
I
Brethenou
P
P
Cochet
C
C
Amalric
F
F
Bouche
G
G
D000818:Animals; D016466:CHO Cells; D047390:Casein Kinase II; D002417:Cattle; D002460:Cell Line; D006224:Cricetinae; D004789:Enzyme Activation; D016222:Fibroblast Growth Factor 2 / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000235:genetics; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D016601:RNA-Binding Proteins; D013379:Substrate Specificity; D000097796:Nucleolin
D047390:Casein Kinase II; D016222:Fibroblast Growth Factor 2; D009687:Nuclear Proteins; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D016601:RNA-Binding Proteins; D000097796:Nucleolin