Go directly (or indirectly) to Gq

Molecular mechanisms of go signaling

Go is the most abundant G protein in the central nervous system, where it comprises about 1% of membrane protein in mammalian brains. It functions to couple cell surface receptors to intercellular effectors, which is a critical process for cells to receive, interpret and respond to extracellular signals. Go protein belongs to the pertussis toxin-sensitive Gi/Go subfamily of G proteins. A number of G-protein-coupled receptors transmit stimuli to intercellular effectors through Go. Go regulates several cellular effectors, including ion channels, enzymes, and even small GTPases to modulate cellular function. This review summarizes some of the advances in Go research and proposes areas to be further addressed in exploring the functional role of Go.

Regulation of retrograde signaling at neuromuscular junctions by the novel C2 domain protein AEX-1

Retrograde signaling from postsynaptic cells to presynaptic neurons is essential for regulation of synaptic development, maintenance, and plasticity. Here we report that the novel protein AEX-1 controls retrograde signaling at neuromuscular junctions in C. elegans. aex-1 mutants show neural defects including reduced presynaptic activity and abnormal localization of the synaptic vesicle fusion protein UNC-13. Muscle-specific AEX-1 expression rescues these defects but neuron-specific expression does not. AEX-1 has an UNC-13 homologous domain and appears to regulate exocytosis in muscles. This retrograde signaling requires prohormone-convertase function in muscles, suggesting that a peptide is the retrograde signal. This signal regulates synaptic vesicle release via the EGL-30 Gq(alpha) protein at presynaptic terminals.

Dopamine signaling in Caenorhabditis elegans-potential for parkinsonism research

The nematode Caenorhabditis elegans is an attractive model system for the study of many biological processes. It possesses a simple nervous system with known anatomy and connectivity, is conveniently and cheaply cultured in the laboratory, and is amenable to many genetic manipulations that are impossible in mammalian systems. The recent completion of the C. elegans genome sequence provides a rich resource of genomic and bioinformatic data to researchers in diverse fields. This organism, however, has been underexploited in the studies of many basic processes related to nervous system function, neuropsychiatric disorders and neuromuscular function. Anatomical, biochemical, behavioral, pharmacological and genetic evidence accumulated to date strongly suggests that dopamine is used as a neurotransmitter by C. elegans, and that its effects are mediated through pathway(s) that share many features with those of mammals. DNA sequence analysis reveals genes highly homologous to those encoding mammalian dopamine receptors. Probably, C. elegans has dopamine receptors that transduce environmental cues into behaviors, and these receptors pharmacologically most closely resemble the D2 family. Here we present a review of the current state of research into the dopamine system of the worm, focussing on its potential for use in the study of biological processes related to parkinsonism.