RT info:eu-repo/semantics/article
T1 Inability of the acidic fibroblast growth factor mutant K132E to stimulate DNA synthesis after translocation into cells
A1 Klingenberg, Olav
A1 Wiedlocha, Antoni
A1 Rapak, Andrzej
A1 Muñoz Martínez, Raquel
A1 Falnes, Pål
A1 Olsnes, Sjur
K1 DNA synthesis
K1 Replicación de ADN
AB Acidic fibroblast growth factor (aFGF) is a potent mitogen. It acts through activation of specific cell surface receptors leading to intracellular tyrosine phosphorylation cascades, but several reports also indicate that aFGF enters cells and that it has an intracellular function as well. The aFGF(K132E) mutant binds to and activates fibroblast growth factor receptors equally strongly as the wild-type, but it is a poor mitogen. We demonstrate that aFGF(K132E) enters NIH 3T3 cells and is transported to the nuclear fraction like wild-type aFGF. A fusion protein of aFGF(K132E) and diphtheria toxin A-fragment (aFGF(K132E)-DT-A) and a similar fusion protein containing wild-type aFGF (aFGF-DT-A) were reconstituted with diphtheria toxin B-fragment. Both fusion proteins were translocated to the cytosol by the diphtheria toxin pathway and subsequently recovered from the nuclear fraction. Whereas translocation of aFGF-DT-A stimulated DNA synthesis in U2OSDR1 cells lacking functional fibroblast growth factor receptors, aFGF(K132E)-DT-A did not. The mutation disrupts a protein kinase C phosphorylation site in the growth factor making it unable to be phosphorylated. The data indicate that a defect in the intracellular action of aFGF(K132E) is the reason for its strongly reduced mitogenicity, possibly due to inability to be phosphorylated.
PB American Society for Biochemistry and Molecular Biology
SN 0021-9258
YR 1998
FD 1998
LK http://uvadoc.uva.es/handle/10324/41004
UL http://uvadoc.uva.es/handle/10324/41004
LA eng
NO Journal of Biological Chemistry, 1998, vol. 273, n. 18. p. 11164-11172
NO Producción Científica
DS UVaDOC
RD 22-nov-2024