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Published on: September 26, 2013
Probable occurrence of toxin-susceptible G proteins in the nematode Caenorhabditis elegans
1Department of Physiological Chemistry, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Abstract:
Pertussis toxin, islet-activating protein (IAP), and cholera toxin ADP-ribosylated 40 kDa and 45 kDa proteins in membrane preparations from Caenorhabditis elegans. Proteins with the same molecular weights were recognized in the same membranes by an antibody that had been raised against a peptide common to alpha-subunits of mammalian alpha beta gamma-heterotrimeric G proteins. The antibody produced immunoprecipitation with the 40 kDa protein 32P-labeled by IAP. A 35 kDa protein immunochemically indistinguishable from the beta-component of mammalian G proteins was also found in C. elegans membranes. The membranes displayed adenylate cyclase activity which was highly sensitive to forskolin and GTP analogues, whose action was antagonized by GDP beta S. Receptor-coupled regulation of adenylate cyclase thus appears to be mediated by mammalian-type G proteins in C. elegans as well.
Insights
Researchers found that Caenorhabditis elegans membranes contain mammalian-type G proteins. These proteins are involved in regulating adenylate cyclase activity, similar to their mammalian counterparts.
Area of Science:
- Molecular Biology
- Biochemistry
- Neuroscience
Background:
- G proteins are crucial signal transducers in eukaryotes.
- Understanding G protein function in model organisms like C. elegans provides insights into conserved biological pathways.
Purpose of the Study:
- To investigate the presence and function of G proteins in Caenorhabditis elegans.
- To determine if C. elegans G proteins mediate receptor-coupled adenylate cyclase activity.
Main Methods:
- ADP-ribosylation of membrane proteins using pertussis toxin, islet-activating protein (IAP), and cholera toxin.
- Immunoprecipitation using an antibody against mammalian G protein alpha-subunits.
- Assay of adenylate cyclase activity in response to forskolin, GTP analogues, and GDP beta S.
Main Results:
- Identified 40 kDa and 45 kDa proteins in C. elegans membranes ADP-ribosylated by toxins.
- An antibody against mammalian G protein alpha-subunits recognized these proteins.
- A 35 kDa protein immunochemically similar to mammalian G protein beta-subunit was detected.
- Adenylate cyclase activity was sensitive to forskolin and GTP analogues, inhibited by GDP beta S.
Conclusions:
- Caenorhabditis elegans possesses mammalian-type G proteins.
- These G proteins appear to mediate receptor-coupled regulation of adenylate cyclase activity in C. elegans.
