Transthyretin binds to glucose-regulated proteins and is subjected to endocytosis by the pancreatic β-cell

Nancy Dekki, Essam Refai, Rebecka Holmberg, Martin Köhler, Hans Jörnvall, Per Olof Berggren, Lisa Juntti-Berggren

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

Transthyretin (TTR) is a functional protein in the pancreatic b-cell. It promotes insulin release and protects against β-cell death. We now demonstrate by ligand blotting, adsorption to specific magnetic beads, and surface plasmon resonance that TTR binds to glucose-regulated proteins (Grps)78, 94, and 170, which are members of the endoplasmic reticulum chaperone family, but Grps78 and 94 have also been found at the plasma membrane. The effect of TTR on changes in cytoplasmic free Ca 2+ concentration ([Ca 2+] i) was abolished if the cells were treated with either dynasore, a specific inhibitor of dynamin GTPase that blocks clathrin-mediated endocytosis, or an antibody against Grp78, that prevents TTR from binding to Grp78. The conclusion is that TTR binds to Grp78 at the plasma membrane, is internalized into the β-cell via a clathrin-dependent pathway, and that this internalization is necessary for the effects of TTR on β-cell function.

Original languageEnglish (US)
Pages (from-to)1733-1743
Number of pages11
JournalCellular and Molecular Life Sciences
Volume69
Issue number10
DOIs
StatePublished - May 2012

Keywords

  • Dynasore
  • Glucose-regulated proteins
  • Pancreatic β-cell
  • Surface plasmon resonance
  • Transthyretin

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Molecular Medicine
  • Pharmacology
  • Cellular and Molecular Neuroscience

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    Dekki, N., Refai, E., Holmberg, R., Köhler, M., Jörnvall, H., Berggren, P. O., & Juntti-Berggren, L. (2012). Transthyretin binds to glucose-regulated proteins and is subjected to endocytosis by the pancreatic β-cell. Cellular and Molecular Life Sciences, 69(10), 1733-1743. https://doi.org/10.1007/s00018-011-0899-8