Clathrin-mediated endocytosis is required for compensatory regulation of GLR-1 glutamate receptors after activity blockade

Proc Natl Acad Sci U S A. 2004 Mar 2;101(9):3190-5. doi: 10.1073/pnas.0306156101. Epub 2004 Feb 23.

Abstract

Chronic changes in neural activity trigger a variety of compensatory homeostatic mechanisms by which neurons maintain a normal level of synaptic input. Here we show that chronic activity blockade triggers a compensatory change in the abundance of GLR-1, a Caenorhabditis elegans glutamate receptor. In mutants lacking a voltage-dependent calcium channel (unc-2) or a vesicular glutamate transporter (VGLUT; eat-4), the abundance of GLR-1 in the ventral nerve cord was increased. Similarly, the amplitude of glutamate-evoked currents in ventral cord interneurons was increased in eat-4 VGLUT mutants compared with wild-type controls. The effects of eat-4 VGLUT mutations on GLR-1 abundance in the ventral cord were eliminated in double mutants lacking both the clathrin adaptin protein unc-11 AP180 and eat-4 VGLUT. In contrast, mutations that decreased ubiquitination of GLR-1 did not prevent increased ventral cord abundance of GLR-1 in eat-4 VGLUT mutants. Taken together, our results suggest that GLR-1 is regulated in a homeostatic manner and that this effect depends on clathrin-mediated endocytosis but does not require ubiquitination of GLR-1.

Publication types

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

MeSH terms

  • Animals
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / physiology
  • Calcium Channels / physiology
  • Clathrin / physiology*
  • Endocytosis / physiology*
  • Gene Expression Regulation / physiology
  • Glutamic Acid / metabolism*
  • Glutamic Acid / pharmacology
  • Models, Biological
  • Patch-Clamp Techniques
  • Receptors, AMPA
  • Receptors, Glutamate / genetics*
  • Receptors, Glutamate / physiology
  • Recombinant Proteins / metabolism
  • Synapses / physiology*
  • Ubiquitin / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Calcium Channels
  • Clathrin
  • Receptors, AMPA
  • Receptors, Glutamate
  • Recombinant Proteins
  • Ubiquitin
  • glr-1 protein, C elegans
  • Glutamic Acid