PGF2alpha increases FGF-2 and FGFR2 trafficking in Py1a rat osteoblasts via clathrin independent and importin beta dependent pathway.
Previous studies showed that prostaglandin F2alpha (PGF2alpha) stimulated fibroblast growth factor-2 (FGF-2) and fibroblast growth factor receptor 2 (FGFR2) cytosolic and nuclear accumulation, however, the endocytic pathway has not been elucidated. This study demonstrates that although PGF2alpha increased the formation of clathrin-coated structures in Py1a rat osteoblasts, they were not involved in FGF-2 and FGFR2 trafficking. PGF2alpha increased binding of FGF-2 and FGFR2 and co-localization of reactive sites in addition to nuclear translocation at the nuclear pore complex level. FGF-2 and FGFR2 were in close spatial correlation with importin beta, further supporting nuclear import of the FGF-2/FGFR2 complex. Immunogold and immunofluorescence techniques as well as Western blotting demonstrated increased importin beta protein labeling in response to PGF2alpha. Similar to PGF2alpha, phorbol 12-myristate 13-acetate (PMA) also increased importin beta protein. These data strongly suggest that prostaglandins may regulate osteoblast metabolism via FGF-2/FGFR2/importin beta nuclear trafficking.
Marchetti
Luigi
L
Department of Comparative Morphology and Biochemistry, University of Camerino, Camerino (MC)/Italy. luigi.marchetti@unicam.it
Sabbieti
Maria G
MG
Agas
Dimitrios
D
Menghi
Maura
M
Materazzi
Giovanni
G
Menghi
Giovanna
G
Hurley
Marja M
MM
D000818:Animals; D002478:Cells, Cultured; D002966:Clathrin / Q000378:metabolism*; D015237:Dinoprost / Q000378:metabolism / Q000494:pharmacology*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D010006:Osteoblasts / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport; D051381:Rats; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000378:metabolism*; D015398:Signal Transduction; D028961:beta Karyopherins / Q000378:metabolism*
D002966:Clathrin; D028961:beta Karyopherins; D016222:Fibroblast Growth Factor 2; D015237:Dinoprost; D051497:Receptor, Fibroblast Growth Factor, Type 2