Regulation of the inositol 1,4,5-trisphosphate receptor type I by O-GlcNAc glycosylation

J Neurosci. 2007 Dec 12;27(50):13813-21. doi: 10.1523/JNEUROSCI.2069-07.2007.

Abstract

The inositol 1,4,5-trisphosphate (InsP3) receptor type I (InsP3R-I) is the principle channel for intracellular calcium (Ca2+) release in many cell types, including central neurons. It is regulated by endogenous compounds like Ca2+ and ATP, by protein partners, and by posttranslational modification. We report that the InsP3R-I is modified by O-linked glycosylation of serine or threonine residues with beta-N-acetylglucosamine (O-GlcNAc). The level of O-GlcNAcylation can be altered in vitro by the addition of the enzymes which add [OGT (O-GlcNActransferase)] or remove (O-GlcNAcase) this sugar or by loading cells with UDP-GlcNAc. We monitored the effects of this modification on InsP3R function at the single-channel level and on intracellular Ca2+ transients. Single-channel activity was monitored with InsP3R incorporated into bilayers; Ca2+ signaling was monitored using cells loaded with a Ca2+-sensitive fluorophore. We found that channel activity was decreased by the addition of O-GlcNAc and that this decrease was reversed by removal of the sugar. Similarly, cells loaded with UDP-GlcNAc had an attenuated response to uncaging of InsP3. These results show that O-GlcNAcylation is an important regulator of the InsP3R-I and suggest a mechanism for neuronal dysfunction under conditions in which O-GlcNAc is high, such as diabetes or physiological stress.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology
  • Cells, Cultured
  • Cerebellum / chemistry
  • Cerebellum / metabolism
  • Glucosamine / analogs & derivatives*
  • Glucosamine / chemistry
  • Glucosamine / metabolism
  • Glycosylation
  • Inositol 1,4,5-Trisphosphate / analogs & derivatives
  • Inositol 1,4,5-Trisphosphate / metabolism
  • Inositol 1,4,5-Trisphosphate / pharmacology
  • Inositol 1,4,5-Trisphosphate Receptors / chemistry*
  • Inositol 1,4,5-Trisphosphate Receptors / metabolism*
  • Interneurons / drug effects
  • Interneurons / metabolism*
  • Lipid Bilayers / chemistry
  • Mice
  • Microsomes / chemistry
  • N-Acetylglucosaminyltransferases / chemistry
  • N-Acetylglucosaminyltransferases / metabolism
  • Organ Culture Techniques
  • Patch-Clamp Techniques
  • Rats
  • Ultraviolet Rays
  • Uridine Diphosphate N-Acetylglucosamine / metabolism
  • Uridine Diphosphate N-Acetylglucosamine / pharmacology
  • beta-N-Acetylhexosaminidases / chemistry

Substances

  • Inositol 1,4,5-Trisphosphate Receptors
  • Lipid Bilayers
  • inositol 1,4,5-trisphosphate 1-(2-nitrophenyl)ethyl ester
  • Uridine Diphosphate N-Acetylglucosamine
  • N-acetylglucopyranosylamine
  • Inositol 1,4,5-Trisphosphate
  • N-Acetylglucosaminyltransferases
  • O-GlcNAc transferase
  • hexosaminidase C
  • beta-N-Acetylhexosaminidases
  • Glucosamine