Protostome Hormone

Identification of a gonadotropin-releasing hormone receptor orthologue in Caenorhabditis elegans (Goog) 
Full length article.  "The Caenorhabditis elegans genome is known to code for at least 1149 G protein-coupled receptors (GPCRs), but the GPCR(s) critical to the regulation of reproduction in this nematode are not yet known. This study examined whether GPCRs orthologous to human gonadotropin-releasing hormone receptor (GnRHR) exist in C. elegans.

"Our sequence analyses indicated the presence of two proteins in C. elegans, one of 401 amino acids ... and another of 379 amino acids... with 46.9% and 44.7% nucleotide similarity to human GnRHR1 and GnRHR2, respectively. Like human GnRHR1, structural analysis of the C. elegans GnRHR1 orthologue (Ce-GnRHR) predicted a rhodopsin family member with 7 transmembrane domains, G protein coupling sites and phosphorylation sites for protein kinase C. ... in the pharynx, Ce-GnRHR was localized to the myofilament lattice of the pharyngeal musculature, suggesting a functional role for Ce-GnRHR signaling in the coupling of food intake with reproduction. Phylogenetic analyses support an early evolutionary origin of GnRH-like receptors ...

Gonadotropin-releasing hormone receptor (Wiki) 
"The gonadotropin-releasing hormone receptor (GNRHR), also known as the luteinizing hormone releasing hormone receptor (LHRHR), is a member of the seven-transmembrane, G-protein coupled receptor (GPCR) family."  "Activation of GNRHR ultimately causes the release of follicle stimulating hormone (FSH) and luteinizing hormone (LH)."

Nuclear hormone receptors in C. elegans (Goog) 
"An early invention of metazoan signal transduction, nuclear receptors (NRs) comprise a family of transcription factors often regulated by small lipophilic molecules, such as steroids, retinoids, bile and fatty acids, that mediate endocrine control (Mangelsdorf et al., 1995).

Nuclear receptors (NRs) are transcription factors typically regulated by lipophilic hormones, which coordinate metazoan metabolism, development and homeostasis.C. elegans has undergone a remarkable expansion of the family, harboring 284 of these receptors in its genome. Approximately 20 of them have been analyzed genetically, most of which correspond to conserved homologs in other metazoans. These NRs variously affect broad life history traits such as sex determination, molting, developmental timing, diapause, and life span. They also impact neural development, axon outgrowth and neuronal identity.

Nuclear receptor (Wiki)   
"In the field of molecular biology, nuclear receptors are a class of proteins found within the interior of cells that are responsible for sensing the presence of steroid and thyroid hormones and certain other molecules. In response, these receptors work in concert with other proteins to regulate the expression of specific genes thereby controlling the development, homeostasis, and metabolism of the organism.

Nuclear receptors have the ability to directly bind to DNA and regulate the expression of adjacent genes, hence these receptors are classified as transcription factors.[1][2] The regulation of gene expression by nuclear receptors only happens when a ligand—a molecule which affects the receptor's behavior—is present. More specifically, ligand binding to a nuclear receptor results in a conformational change in the receptor which in turn activates the receptor resulting in up-regulation of gene expression.

A unique property of nuclear receptors which differentiate them from other classes of receptors is their ability to directly interact with and control the expression of genomic DNA. Consequently nuclear receptors play key roles in both embryonic development and adult homeostasis.

Whole-Genome Analysis of 60 G Protein-Coupled Receptors in Caenorhabditis elegan (Goog) 
"G protein-coupled receptors (GPCRs) are the largest family of genes in animal genomes and represent more than 2% of genes in humans and C. elegans. These evolutionarily conserved seven-transmembrane proteins transduce a diverse range of signals."