Pancreatic Reg I Binds MKP-1 and Regulates Cyclin D in Pancreatic-Derived Cells

Cathy M. Mueller, Hong Zhang, Michael E. Zenilman

Research output: Contribution to journalArticle

Abstract

Background: The pancreatic regenerating (reg I) gene and its protein product are derived from acinar cells and are mitogenic to β- and ductal cells. We studied the mechanism of this mitogenic response. Materials and methods: ARIP (rat ductal) and RIN 1046-38 (rat β-) cell lines were exposed to exogenous reg I in culture or transfected with a reg I expression vector. Mitogenesis was assessed by MTS assay (CellTiter 96; Promega, Inc., Madison, WI), and cellular mRNA was subjected to gene microarray analysis to determine signal transduction pathways. Yeast two-hybrid technology was then used to determine intracellular binding of reg I protein. Results: Cells exposed to exogenous reg I showed a mitogenic response; cells transfected with reg I expression vector showed inhibited growth. Microarray analysis of the former showed induction of cyclin pathways and mitogen-activated protein kinase phosphatase (MKP-1); cyclins were inhibited in the latter. Northern analysis confirmed gene induction of cyclin D1 and MKP-1; JNK was phosphorylated prior to expression of both. Yeast two-hybrid analysis confirmed a protein-protein interaction with MKP-1; this was confirmed by immunoprecipitation. Conclusions: Pancreatic-derived cells exposed to reg I grow by activation of signal transduction pathways involving the mitogen-activated protein kinase phosphatases and cyclins, with concomitant induction of MKP-1. However, high intracellular levels of reg I lead to decreased growth, likely via a binding to and inactivation of MKP-1. Inhibition of cell growth, and possible induction of apoptosis, may lead to differentiation of these cells to other cell types.

Original languageEnglish (US)
Pages (from-to)137-143
Number of pages7
JournalJournal of Surgical Research
Volume150
Issue number1
DOIs
StatePublished - Nov 2008

Keywords

  • EXTL3
  • MKP-1
  • cyclin D1
  • mitogenesis
  • pancreatic ductal cells
  • pancreatic reg I
  • pancreatic β-cells

ASJC Scopus subject areas

  • Surgery

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