The molecular, cellular and functional organization of metabotropic glutamate receptors in Caenorhabditis elegans

Dillon, James Charles (2007) The molecular, cellular and functional organization of metabotropic glutamate receptors in Caenorhabditis elegans. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

It is now apparent that the C-terminal domain of membrane bound receptors serves as the foundation upon which large multi-protein intracellular signalling complexes are constructed. Such complexes enlist scaffolding proteins that orchestrate the receptors compartmental targeting, subcellular anchoring and signalling. To identify mgl-1 scaffolding proteins the intercellular C-terminal was utilised to perform a LexA yeast-2-hybrid screen. Three proteins were prioritised from the screen that harboured protein interaction domains with known functions in scaffolding receptor signalling complexes. These were encoded by the genes ptp-1, mpz-1 and tag-60. The cellular expression of each gene has been defined and discussed. The co-expression of mpz-1 and mg1-1 in the pharyngeal nervous system suggested mpz-1 may organise mgl-1 signalling in this neural circuit. To examine this the function of mgl-1 was tested in the two available mpz-1 mutant strains; mpz-1(tm1136) and mpz-1(gk273/+) and the trans-heterozygote mpz-1(tm1136/gk273), by using the pharyngeal preparation as an assay of mgl-1function.

cDNA analysis predicts both of the mutant transcripts do not encode MPZ-1 protein, however, the function of mgl-1 was intact in the mutant strains. In the absence of any disruption to mg1-1 signalling in the mpz-1 mutants further work is required to determine the relevance of the mpz-1 interaction to mgl-1 function. This study has provided the first functional description of an mgl subtype in C. elegans. In doing so this has identified a bio-assay for investigating the organisation of mgl-1 signalling by interacting proteins in vivo.