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Titolo:
PROTEIN-KINASE C-DEPENDENT DOWN-REGULATION OF BASIC FIBROBLAST GROWTH-FACTOR (FGF-2) RECEPTOR BY PHORBOL ESTER AND EPIDERMAL GROWTH-FACTOR IN PORCINE GRANULOSA-CELLS
Autore:
ASAKAI R; AKITA Y; TAMURA K; KENMOTSU N; AOYAMA Y;
Indirizzi:
TOKYO MED & DENT UNIV,MED RES INST,DEPT ENDOCRINOL,BUNKYO KU,1-5-45 YUSHIMA TOKYO 113 JAPAN TOKYO METROPOLITAN INST MED SCI,DEPT MOLEC BIOL TOKYO 113 JAPAN
Titolo Testata:
Endocrinology
fascicolo: 8, volume: 136, anno: 1995,
pagine: 3470 - 3479
SICI:
0013-7227(1995)136:8<3470:PCDOBF>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
FOLLICLE-STIMULATING-HORMONE; PLASMINOGEN-ACTIVATOR PRODUCTION; LUTEINIZING-HORMONE; PROMOTER REGION; CYCLIC-AMP; OVARIAN; STEROIDOGENESIS; DIFFERENTIATION; INHIBITION; BINDING;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
46
Recensione:
Indirizzi per estratti:
Citazione:
R. Asakai et al., "PROTEIN-KINASE C-DEPENDENT DOWN-REGULATION OF BASIC FIBROBLAST GROWTH-FACTOR (FGF-2) RECEPTOR BY PHORBOL ESTER AND EPIDERMAL GROWTH-FACTOR IN PORCINE GRANULOSA-CELLS", Endocrinology, 136(8), 1995, pp. 3470-3479

Abstract

The regulation of the basic fibroblast growth factor (bFGF, or FGF-2)receptor on porcine granulosa cells was studied. Receptor levels before and after cell differentiation in vivo and in vitro did not show any significant changes. Dibutyryl cAMP and the protein kinase A (PKA) inhibitor H-8 had no effect on bFGF binding. These results suggest thatPKA was not involved in the receptor expression. Treatment of the granulosa cells with phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, progressively decreased the number of bFGF receptors to about 20% of their initial levels after 8 h, and this effect occurred in a concentration- and time- dependent manner. Similarly, synthetic diacylglycerol also inhibited bFGF binding. The highly specific PKC inhibitor GF109203X completely prevented the reduction of bFGF binding by PMA and diacylglycerol. Kinetic analyses of the turnover of cell surface bFGF receptors in the presence of cycloheximide showed that PMA accelerated loss of receptors from the cell surface, suggestingthe enhanced receptor internalization by PMA resulting in the receptor reduction. PMA did not influence steady-state FGF receptor messengerRNA levels. PMA induced an increased PKC activity in the membrane fraction, and among PMA sensitive PKC alpha, beta II, delta and epsilon, only PKC alpha was readily detected by immunoblotting and translocatedto the membrane fraction. PMA-pretreated cells showed negligible effect on c-fos messenger RNA induction in response to bFGF stimulation, indicating a functional reduction of receptors. When cells were incubated with epidermal growth factor, receptor levels were reduced, but this effect was not observed in the presence of GF109203X. These results suggest that the bFGF receptor in porcine granulosa cells is regulatedby the PKC, not PKA, pathway in an isoenzyme-specific fashion and that its possible mechanism may involve regulation of receptor internalization.

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Documento generato il 30/11/20 alle ore 15:12:40