Role of the C-terminal di-leucine motif of 5-HT1A and 5-HT1B serotonin receptors in plasma membrane targeting

J Cell Sci. 2006 Oct 15;119(Pt 20):4276-84. doi: 10.1242/jcs.03189. Epub 2006 Sep 26.

Abstract

The 5-HT1A and 5-HT1B serotonin receptors exhibit different subcellular localizations in neurons. Evidence has been reported that the C-terminal domain is involved in the somato-dendritic and axonal targeting of 5-HT1AR and 5-HT1BR, respectively. Here we analyzed the consequences of the mutation of a di-leucine motif and palmitoylated cysteines within this domain. Replacement of I414-I415 by a di-alanine in 5-HT1AR led to endoplasmic reticulum (ER) sequestration of the corresponding mutant expressed in cell lines as well as in hippocampal neurons in culture. Furthermore, di-leucine-mutated receptors were unable to bind 5-HT1A agonists and presented a major deficit in their glycosylation state, suggesting that they are misfolded. By contrast, mutation of the di-leucine motif in the C-terminal domain of 5-HT1BR had no major consequence on its subcellular targeting. However, in the case of the 1ActB chimera (substitution of the C-terminal domain of the 5-HT1BR into 5-HT1AR), this mutation was also found to cause sequestration within the ER. Replacement of palmitoylated cysteines by serines had no consequence on either receptor type. These data indicate that the di-leucine motif of the 5-HT1AR and 5-HT1BR tails is implicated in proper folding of these receptors, which is necessary for their ER export.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites / genetics
  • COS Cells
  • Cell Membrane / metabolism*
  • Cells, Cultured
  • Chlorocebus aethiops
  • Cysteine / genetics
  • Cysteine / metabolism
  • Endoplasmic Reticulum / metabolism
  • Fluorescent Antibody Technique, Indirect / methods
  • Leucine / genetics
  • Leucine / metabolism*
  • Leucine / physiology
  • Molecular Sequence Data
  • Mutation / genetics
  • Protein Binding
  • Protein Transport / drug effects
  • Receptor, Serotonin, 5-HT1A / genetics
  • Receptor, Serotonin, 5-HT1A / metabolism*
  • Receptor, Serotonin, 5-HT1B / genetics
  • Receptor, Serotonin, 5-HT1B / metabolism*
  • Serotonin 5-HT1 Receptor Agonists
  • Serotonin Receptor Agonists / pharmacology
  • Swine

Substances

  • Receptor, Serotonin, 5-HT1B
  • Serotonin 5-HT1 Receptor Agonists
  • Serotonin Receptor Agonists
  • Receptor, Serotonin, 5-HT1A
  • Leucine
  • Cysteine