Recycling of the dense-core vesicle membrane protein phogrin in Min6 beta-cells

Biochem Biophys Res Commun. 2004 Nov 19;324(3):1004-10. doi: 10.1016/j.bbrc.2004.09.147.

Abstract

Phogrin (IA2-beta) is an integral membrane protein of dense-core vesicles in neuroendocrine cells. We have examined the recycling of endogenous phogrin following exocytosis in insulin secreting Min6 beta-cells by monitoring stimulus dependent-uptake of antibodies directed against the lumenal domain of the protein. While low levels of internalized phogrin accumulated in LAMP1-positive lysosomes, more than 35% of internalized phogrin recycled back to an insulin-positive compartment and could return to the cell surface during a second exocytic stimulation. The recycling phogrin transited a syntaxin 6-positive compartment but did not appear to go through the TGN38-positive trans Golgi network. The results suggest a model in which secretory membrane components can recycle from the endosomal system to immature secretory granules without interaction with the major portion of the TGN.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Line
  • Cell Membrane / metabolism
  • Chickens
  • Endocytosis
  • Exocytosis
  • Golgi Apparatus / metabolism*
  • Image Processing, Computer-Assisted
  • Insulin / metabolism*
  • Islets of Langerhans / metabolism*
  • Lysosome-Associated Membrane Glycoproteins
  • Lysosomes / metabolism
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism
  • Mice
  • Microscopy, Fluorescence
  • Protein Structure, Tertiary
  • Protein Tyrosine Phosphatases / chemistry
  • Qa-SNARE Proteins
  • Rabbits
  • Receptor-Like Protein Tyrosine Phosphatases, Class 8
  • Time Factors
  • trans-Golgi Network / metabolism

Substances

  • Insulin
  • LAMP1 protein, human
  • Lysosome-Associated Membrane Glycoproteins
  • Membrane Glycoproteins
  • Membrane Proteins
  • Qa-SNARE Proteins
  • Tgoln1 protein, mouse
  • Tgoln2 protein, mouse
  • PTPRN2 protein, human
  • Protein Tyrosine Phosphatases
  • Receptor-Like Protein Tyrosine Phosphatases, Class 8