title: Cloning of an intracellular protein that binds selectively to mitogenic acidic fibroblast growth factor.
abstract: In addition to its extracellular action, there is evidence that acidic fibroblast growth factor (aFGF) acts inside cells. To identify intracellular proteins interacting with aFGF, we screened a HeLa cell library in the yeast two-hybrid system using pLex-aFGF as a bait. A clone binding to aFGF, but not to the non-mitogenic mutant aFGF-K132E, was isolated and characterized. The insert contained an open reading frame corresponding to a novel protein of 42 kDa. The protein, termed aFGF intracellular binding protein (FIBP), is mainly hydrophilic and does not contain an N-terminal signal sequence. In vitro-translated FIBP bound specifically to a fusion protein of maltose-binding protein and aFGF. FIBP became post-translationally associated with microsomes added to the cell-free protein synthesizing system, and the membrane-associated protein bound aFGF with high efficiency. Immunoblots and fluorescence microscopy demonstrated that the protein is present in nuclei and, to a lesser extent, associated with mitochondria and other cytoplasmic membranes. The possibility is discussed that FIBP may be involved in the mitogenic action of aFGF.
authors.affiliation: Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, 0310 Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Kolpakova
authors.forename: A
authors.initials: A
authors.lastname: Wiedłocha
authors.forename: H
authors.initials: H
authors.lastname: Stenmark
authors.forename: O
authors.initials: O
authors.lastname: Klingenberg
authors.forename: P O
authors.initials: PO
authors.lastname: Falnes
authors.forename: S
authors.initials: S
authors.lastname: Olsnes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D004261:DNA Replication; D018076:DNA, Complementary; D016220:Fibroblast Growth Factor 1 / Q000235:genetics / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008934:Mitogens / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism; D014709:Vero Cells
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; C116274:FIBP protein, human; D008565:Membrane Proteins; D008934:Mitogens; D012333:RNA, Messenger; D016220:Fibroblast Growth Factor 1