STR-33, a novel G protein-coupled receptor that regulates locomotion and egg laying in Caenorhabditis elegans

J Biol Chem. 2011 Nov 18;286(46):39860-70. doi: 10.1074/jbc.M111.241000. Epub 2011 Sep 21.


Despite their predicted functional importance, most G protein-coupled receptors (GPCRs) in Caenorhabditis elegans have remained largely uncharacterized. Here, we focused on one GPCR, STR-33, encoded by the str-33 gene, which was discovered through a ligand-based screening procedure. To characterize STR-33 function, we performed UV-trimethylpsolaren mutagenesis and isolated an str-33-null mutant. The resulting mutant showed hypersinusoidal movement and a hyperactive egg-laying phenotype. Two types of egg laying-related mutations have been characterized: egg laying-deficient (Egl-d) and hyperactive egg laying (Egl-c). The defect responsible for the egg laying-deficient Egl-d phenotype is related to Gα(q) signaling, whereas that responsible for the opposite, hyperactive egg-laying Egl-c phenotype is related to Gα(o) signaling. We found that the hyperactive egg-laying defect of the str-33(ykp001) mutant is dependent on the G protein GOA-1/Gα(o). Endogenous acetylcholine suppressed egg laying in C. elegans via a Gα(o)-signaling pathway by inhibiting serotonin biosynthesis or release from the hermaphrodite-specific neuron. Consistent with this, in vivo expression of the serotonin biosynthetic enzyme, TPH-1, was up-regulated in the str-33(ykp001) mutant. Taken together, these results suggest that the GPCR, STR-33, may be one of the neurotransmitter receptors that regulates locomotion and egg laying in C. elegans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / genetics
  • Acetylcholine / metabolism
  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Female
  • GTP-Binding Protein alpha Subunits, Gi-Go / genetics
  • GTP-Binding Protein alpha Subunits, Gi-Go / metabolism*
  • GTP-Binding Protein alpha Subunits, Gq-G11 / genetics
  • GTP-Binding Protein alpha Subunits, Gq-G11 / metabolism*
  • Locomotion / physiology*
  • Mutagenesis
  • Mutation
  • Neurons / metabolism
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*
  • Receptors, Neurotransmitter / genetics
  • Receptors, Neurotransmitter / metabolism*
  • Reproduction / physiology
  • Serotonin / biosynthesis
  • Serotonin / genetics


  • Caenorhabditis elegans Proteins
  • GOA-1 protein, C elegans
  • Receptors, G-Protein-Coupled
  • Receptors, Neurotransmitter
  • STR-33 protein, C elegans
  • Serotonin
  • GTP-Binding Protein alpha Subunits, Gi-Go
  • GTP-Binding Protein alpha Subunits, Gq-G11
  • Acetylcholine