Phorbol ester-mediated neurotensin secretion is dependent on the PKC-α and -δ isoforms

Jing Li, Mark Hellmich, George H. Greeley, Courtney Townsend, B. Mark Evers

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Neurotensin (NT) plays an important role in gastrointestinal secretion, motility, and growth. The mechanisms regulating NT secretion are not entirely known. Our purpose was to define the role of the PKC signaling pathway in secretion of NT from BON cells, a human pancreatic carcinoid cell line that produces and secretes NT peptide. We demonstrated expression of all 11 PKC isoforms at varying levels in untreated BON cells. Expression of PKC-α, -β2, -δ, and -μ isoforms was most pronounced. Immunofluorescent staining showed PKC-α and -μ expression throughout the cytoplasm and in the membrane. Also, significant fluorescence of PKC-δ was noted in the nucleus and cytoplasm. Treatment with PMA induced translocation of PKC-α, -δ, and -μ from cytosol to membrane. Activation of PKC-α, -δ, and -δ was further confirmed by kinase assays. Addition of PKC-α inhibitor Gö-6976 at a nanomolar concentration, other PKC inhibitors Gö-6983 and GF-109203X, or PKC-δ-specific inhibitor rottlerin significantly inhibited PMA-mediated NT release. Overexpression of either PKC-α or -δ increased PMA-mediated NT secretion compared with control cells. We demonstrated that PMA-mediated NT secretion in BON cells is associated with translocation and activation of PKC-α, -δ, and -μ. Furthermore, inhibition of PKC-α and -δ blocked PMA-stimulated NT secretion, suggesting a critical role for these isoforms in NT release.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume283
Issue number5 46-5
StatePublished - Nov 2002

Fingerprint

Neurotensin
Phorbol Esters
Protein Isoforms
Cytoplasm
Gastrointestinal Motility
Membranes
Secretory Pathway
Carcinoid Tumor
Cytosol
Phosphotransferases
Fluorescence
Staining and Labeling
Cell Line
Peptides

Keywords

  • BON cell line
  • Gut endocrine cells
  • Phorbol ester
  • Protein kinase C

ASJC Scopus subject areas

  • Gastroenterology
  • Physiology

Cite this

Phorbol ester-mediated neurotensin secretion is dependent on the PKC-α and -δ isoforms. / Li, Jing; Hellmich, Mark; Greeley, George H.; Townsend, Courtney; Evers, B. Mark.

In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 283, No. 5 46-5, 11.2002.

Research output: Contribution to journalArticle

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abstract = "Neurotensin (NT) plays an important role in gastrointestinal secretion, motility, and growth. The mechanisms regulating NT secretion are not entirely known. Our purpose was to define the role of the PKC signaling pathway in secretion of NT from BON cells, a human pancreatic carcinoid cell line that produces and secretes NT peptide. We demonstrated expression of all 11 PKC isoforms at varying levels in untreated BON cells. Expression of PKC-α, -β2, -δ, and -μ isoforms was most pronounced. Immunofluorescent staining showed PKC-α and -μ expression throughout the cytoplasm and in the membrane. Also, significant fluorescence of PKC-δ was noted in the nucleus and cytoplasm. Treatment with PMA induced translocation of PKC-α, -δ, and -μ from cytosol to membrane. Activation of PKC-α, -δ, and -δ was further confirmed by kinase assays. Addition of PKC-α inhibitor G{\"o}-6976 at a nanomolar concentration, other PKC inhibitors G{\"o}-6983 and GF-109203X, or PKC-δ-specific inhibitor rottlerin significantly inhibited PMA-mediated NT release. Overexpression of either PKC-α or -δ increased PMA-mediated NT secretion compared with control cells. We demonstrated that PMA-mediated NT secretion in BON cells is associated with translocation and activation of PKC-α, -δ, and -μ. Furthermore, inhibition of PKC-α and -δ blocked PMA-stimulated NT secretion, suggesting a critical role for these isoforms in NT release.",
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AU - Evers, B. Mark

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