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Eukaryotic translation initiation factor 3 subunit e controls intracellular calcium homeostasis by regulation of cav1.2 surface expression.

Author:
  • Pawel Buda
  • Thomas Reinbothe
  • Vini Nagaraj
  • Taman Mahdi
  • Cheng Luan
  • Yunzhao Tang
  • Annika Axelsson
  • Daiqing Li
  • Anders Rosengren
  • Erik Renström
  • Enming Zhang
Publishing year: 2013
Language: English
Publication/Series: PLoS ONE
Volume: 8
Issue: 5
Document type: Journal article
Publisher: Public Library of Science

Abstract english

Inappropriate surface expression of voltage-gated Ca(2+)channels (CaV) in pancreatic ß-cells may contribute to the development of type 2 diabetes. First, failure to increase intracellular Ca(2+) concentrations at the sites of exocytosis impedes insulin release. Furthermore, excessive Ca(2+) influx may trigger cytotoxic effects. The regulation of surface expression of CaV channels in the pancreatic β-cells remains unknown. Here, we used real-time 3D confocal and TIRFM imaging, immunocytochemistry, cellular fractionation, immunoprecipitation and electrophysiology to study trafficking of L-type CaV1.2 channels upon β-cell stimulation. We found decreased surface expression of CaV1.2 and a corresponding reduction in L-type whole-cell Ca(2+) currents in insulin-secreting INS-1 832/13 cells upon protracted (15-30 min) stimulation. This internalization occurs by clathrin-dependent endocytosis and could be prevented by microtubule or dynamin inhibitors. eIF3e (Eukaryotic translation initiation factor 3 subunit E) is part of the protein translation initiation complex, but its effect on translation are modest and effects in ion channel trafficking have been suggested. The factor interacted with CaV1.2 and regulated CaV1.2 traffic bidirectionally. eIF3e silencing impaired CaV1.2 internalization, which resulted in an increased intracellular Ca(2+) load upon stimulation. These findings provide a mechanism for regulation of L-type CaV channel surface expression with consequences for β-cell calcium homeostasis, which will affect pancreatic β-cell function and insulin production.

Keywords

  • Endocrinology and Diabetes

Other

Published
  • Islet patophysiology
  • Diabetes and Endocrinology
  • ISSN: 1932-6203
Erik Renström
E-mail: erik.renstrom [at] med.lu.se

Deputy head of department

Department of Clinical Sciences, Malmö

+46 40 39 11 57

+46 40 39 11 57

Principal investigator

Islet patophysiology

+46 40 39 11 57

+46 40 39 11 57

20-3-308

33

Lund University Diabetes Centre, CRC, SUS Malmö, Entrance 72, House 91:12. SE-205 02 Malmö. Telephone: +46 40 39 10 00