G proteins, chemosensory perception, and the C. elegans genome project: An attractive story

Abstract

Heterotrimeric G proteins, consisting of α, β, and γ subunits, couple ligand‐bound seven transmembrane domain receptors to the regulation of effector proteins and production of intracellular second messengers. G protein signaling mediates the perception of environmental cues in all higher eukaryotic organisms, including yeast, Dictyostelium, plants, and animals. The nematode Caenorhabditis elegans is the first animal to have complete descriptions of its cellular anatomy, cell lineage, neuronal wiring diagram, and genomic sequence. In a recent paper, Jansen et al.(1) used sequence searches of the C. elegans genome database to identify all heterotrimeric G protein genes (20 Gα, 2 Gβ, 2 Gγ). C. elegans encodes one ortholog of each of the four Gα classes found in metazoans and 16 new Gα genes. The orthologous genes are widely expressed, whereas 14 of the divergent Gα genes are almost exclusively expressed in sensory neurons where they may regulate perception and chemotaxis.BioEssays 21:713–717, 1999. © 1999 John Wiley & Sons, Inc.

A gene expression fingerprint of C. elegans embryonic motor neurons

“…With one exception ( dop-3 ), transcripts for all of the known components of these pathways are either enriched ( acy-1 , egl-10 , gpc-2 , kin-2 , pkc-1 ) or detected as EGs ( dgk-1 , egl-8 , egl-16 , gpb-2 , gsa-1 , kin-2 , ric-8 , unc-13 ). Lack of enrichment of some of these components is consistent with the widespread utilization of G-protein signaling pathways in C. elegans neurons and muscle cells [61,62]. As noted above, these data have also revealed several additional enriched transcripts with potential roles in G-protein dependent locomotory behavior.…”

Evolution of the Regulators of G-Protein Signaling Multigene Family in Mouse and Human

“…RC (five genes) and R4 (nine genes) are only present in worms and vertebrates, respectively. The substrate specificities and expression patterns of the RC genes are still being characterized, but a plausible explanation for their rapid expansion is that they interact with the 16 divergent Gi class ␣-subunit genes in specialized cell types in worms [28,29]. G␣ specificity may be altered by a few amino acid substitutions in an RGS protein [30].…”