Protein kinase Cι enhances the transcriptional activity of the porcine P-450 side-chain cleavage insulin-like response element

Randall Urban, Yvonne H. Bodenburg, Jie Jiang, Larry Denner, Jorge Chedrese

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7 Citations (Scopus)

Abstract

IGF-I enhances steroidogenesis in granulosa cells by stimulating the expression of the rate-limiting steroidogenic enzyme, cytochrome P-450 side-chain cleavage (P-450scc). This effect is mediated through an IGF response element (IGFRE) that binds polypyrimidine tract-binding protein (PTB)-associated splicing factor (PSF) and Sp1. Sp1 is essential for activation of the IGFRE, and PSF functions as a repressor. We investigated mechanisms of modulation of the IGFRE by the atypical protein kinase C (PKC)ι in a porcine stable granulosa cell line, JC-410. PKCι was found in nuclear extracts, and levels were increased by IGF-I after 24 and 48 h of treatment. Immunoprecipitation experiments demonstrated that PSF and PKCι associated with each other in nuclear extracts from JC-410 cells. Transient transfection with expression plasmids of kinase-active and kinase-deficient PKCι isoforms enhanced transcriptional activity of the IGFRE regardless of kinase catalytic activity. Depletion of PKCι protein by small interfering RNA suppressed basal IGFRE activity but did not prevent IGF-I stimulation of the IGFRE. We conclude that PKCι enhances transcriptional activity of the porcine P-450scc IGFRE independently of kinase activity by a mechanism involving protein-protein interaction with PSF.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume286
Issue number6 49-6
DOIs
StatePublished - Jun 2004

Fingerprint

Response Elements
Protein Kinase C
Swine
Insulin
Phosphotransferases
Insulin-Like Growth Factor I
Granulosa Cells
Polypyrimidine Tract-Binding Protein
Proteins
Immunoprecipitation
Cytochrome P-450 Enzyme System
Small Interfering RNA
Transfection
Catalyst activity
Protein Isoforms
Plasmids
Chemical activation
Cells
Modulation
Cell Line

Keywords

  • Insulin-like growth factor I
  • Polypyrimidine tract-binding protein-associated splicing factor
  • Protein kinase C iota

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Biochemistry

Cite this

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title = "Protein kinase Cι enhances the transcriptional activity of the porcine P-450 side-chain cleavage insulin-like response element",
abstract = "IGF-I enhances steroidogenesis in granulosa cells by stimulating the expression of the rate-limiting steroidogenic enzyme, cytochrome P-450 side-chain cleavage (P-450scc). This effect is mediated through an IGF response element (IGFRE) that binds polypyrimidine tract-binding protein (PTB)-associated splicing factor (PSF) and Sp1. Sp1 is essential for activation of the IGFRE, and PSF functions as a repressor. We investigated mechanisms of modulation of the IGFRE by the atypical protein kinase C (PKC)ι in a porcine stable granulosa cell line, JC-410. PKCι was found in nuclear extracts, and levels were increased by IGF-I after 24 and 48 h of treatment. Immunoprecipitation experiments demonstrated that PSF and PKCι associated with each other in nuclear extracts from JC-410 cells. Transient transfection with expression plasmids of kinase-active and kinase-deficient PKCι isoforms enhanced transcriptional activity of the IGFRE regardless of kinase catalytic activity. Depletion of PKCι protein by small interfering RNA suppressed basal IGFRE activity but did not prevent IGF-I stimulation of the IGFRE. We conclude that PKCι enhances transcriptional activity of the porcine P-450scc IGFRE independently of kinase activity by a mechanism involving protein-protein interaction with PSF.",
keywords = "Insulin-like growth factor I, Polypyrimidine tract-binding protein-associated splicing factor, Protein kinase C iota",
author = "Randall Urban and Bodenburg, {Yvonne H.} and Jie Jiang and Larry Denner and Jorge Chedrese",
year = "2004",
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language = "English (US)",
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T1 - Protein kinase Cι enhances the transcriptional activity of the porcine P-450 side-chain cleavage insulin-like response element

AU - Urban, Randall

AU - Bodenburg, Yvonne H.

AU - Jiang, Jie

AU - Denner, Larry

AU - Chedrese, Jorge

PY - 2004/6

Y1 - 2004/6

N2 - IGF-I enhances steroidogenesis in granulosa cells by stimulating the expression of the rate-limiting steroidogenic enzyme, cytochrome P-450 side-chain cleavage (P-450scc). This effect is mediated through an IGF response element (IGFRE) that binds polypyrimidine tract-binding protein (PTB)-associated splicing factor (PSF) and Sp1. Sp1 is essential for activation of the IGFRE, and PSF functions as a repressor. We investigated mechanisms of modulation of the IGFRE by the atypical protein kinase C (PKC)ι in a porcine stable granulosa cell line, JC-410. PKCι was found in nuclear extracts, and levels were increased by IGF-I after 24 and 48 h of treatment. Immunoprecipitation experiments demonstrated that PSF and PKCι associated with each other in nuclear extracts from JC-410 cells. Transient transfection with expression plasmids of kinase-active and kinase-deficient PKCι isoforms enhanced transcriptional activity of the IGFRE regardless of kinase catalytic activity. Depletion of PKCι protein by small interfering RNA suppressed basal IGFRE activity but did not prevent IGF-I stimulation of the IGFRE. We conclude that PKCι enhances transcriptional activity of the porcine P-450scc IGFRE independently of kinase activity by a mechanism involving protein-protein interaction with PSF.

AB - IGF-I enhances steroidogenesis in granulosa cells by stimulating the expression of the rate-limiting steroidogenic enzyme, cytochrome P-450 side-chain cleavage (P-450scc). This effect is mediated through an IGF response element (IGFRE) that binds polypyrimidine tract-binding protein (PTB)-associated splicing factor (PSF) and Sp1. Sp1 is essential for activation of the IGFRE, and PSF functions as a repressor. We investigated mechanisms of modulation of the IGFRE by the atypical protein kinase C (PKC)ι in a porcine stable granulosa cell line, JC-410. PKCι was found in nuclear extracts, and levels were increased by IGF-I after 24 and 48 h of treatment. Immunoprecipitation experiments demonstrated that PSF and PKCι associated with each other in nuclear extracts from JC-410 cells. Transient transfection with expression plasmids of kinase-active and kinase-deficient PKCι isoforms enhanced transcriptional activity of the IGFRE regardless of kinase catalytic activity. Depletion of PKCι protein by small interfering RNA suppressed basal IGFRE activity but did not prevent IGF-I stimulation of the IGFRE. We conclude that PKCι enhances transcriptional activity of the porcine P-450scc IGFRE independently of kinase activity by a mechanism involving protein-protein interaction with PSF.

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