NoBP, a nuclear fibroblast growth factor 3 binding protein, is cell cycle regulated and promotes cell growth.
Secreted and nuclear forms of fibroblast growth factor 3 (FGF3) have opposing effects on cells. The secreted form stimulates cell growth and transformation, while the nuclear form inhibits DNA synthesis and cell proliferation. By using the yeast two-hybrid system we have identified a nucleolar FGF3 binding protein (NoBP) which coimmunoprecipitated and colocalized with FGF3 in transfected COS-1 cells. Characterization of the NoBP binding domain of FGF3 exactly matched the sequence requirements of FGF3 for its translocation into the nucleoli, suggesting that NoBP might be the nucleolar binding partner of FGF3 essential for its nucleolus localization. Carboxyl-terminal domains of NoBP contain linear nuclear and nucleolar targeting motifs which are capable of directing a heterologous protein beta-galactosidase to the nucleus and the nucleoli. While NoBP expression was detected in all analyzed proliferating established cell lines, NoBP transcription was rapidly downregulated in the promyelocytic leukemia cell line HL60 when induced to differentiate. Analysis on the expression pattern of NoBP mRNA throughout the cell cycle in HeLa cells synchronized by lovastatin demonstrated a substantial upregulation during the late G(1)/early S phase. NoBP overexpression conferred a proliferating effect onto NIH 3T3 cells and can counteract the inhibitory effect of nuclear FGF3, suggesting a role of NoBP in controlling proliferation in cells. We propose that NoBP is the functional target of nuclear FGF3 action.
Reimers
K
K
Institut für Hämostaseologie und Transfusionsmedizin, Medizinische Fakultät, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany.
Antoine
M
M
Zapatka
M
M
Blecken
V
V
Dickson
C
C
Kiefer
P
P
D016475:3T3 Cells; D021581:Active Transport, Cell Nucleus; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D051518:Fibroblast Growth Factor 3; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D017353:Gene Deletion; D005982:Glutathione Transferase / Q000378:metabolism; D018922:HL-60 Cells; D006367:HeLa Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008148:Lovastatin / Q000494:pharmacology; D051379:Mice; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques; D015854:Up-Regulation; D001616:beta-Galactosidase / Q000378:metabolism
D002352:Carrier Proteins; D018076:DNA, Complementary; C432687:EBNA1BP2 protein, human; C499008:EBP2 protein, S cerevisiae; C499009:Ebna1bp2 protein, mouse; C496444:FGF3 protein, human; C489197:Fgf3 protein, mouse; D051518:Fibroblast Growth Factor 3; D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D005346:Fibroblast Growth Factors; D012313:RNA; D008148:Lovastatin; D005982:Glutathione Transferase; D001616:beta-Galactosidase