scholarly journals EXC-4/CLIC, Gα, and Rho/Rac signaling regulate tubulogenesis in C. elegans

2021 ◽  
Author(s):  
Anthony F Arena ◽  
Daniel D Shaye
Keyword(s):  
G Protein ◽  
Small Gtpases ◽  
Loss Of Function ◽  
C Elegans ◽  
C Terminus ◽  
Evolutionarily Conserved ◽  
Rho Family Gtpases ◽  
Rho Family ◽  
Vessel Development ◽  
G Protein Coupled

The Rho-family of small GTPases, which play crucial roles in development and disease, are regulated by many signal-transduction cascades, including G-protein-coupled receptor (GPCR)-heterotrimeric G-protein (Gα/β/γ) pathways. Using genetic approaches in C. elegans we identified a new role for Gα and Rho/Rac signaling in cell outgrowth during tubulogenesis and show that the Chloride Intracellular Channel (CLIC) protein EXC-4 is an evolutionarily-conserved player in this pathway. The gene exc-4 was identified by its role in tubulogenesis of the excretory canal (ExCa) cell: a unicellular tube required for osmoregulation and fluid clearance. We identified a new exc-4 loss-of-function allele that affects an evolutionarily conserved residue in the C-terminus. Using this mutant we identified genetic interactions between exc-4, Gα's and Rho-family GTPases, defining novel roles for Gα-encoding genes (gpa-12/Gα12/13, gpa-7/Gαi, egl-30/Gαq, and gsa-1/Gαs) and the Rho-family members ced-10/Rac and mig-2/RhoG in ExCa outgrowth. EXC-4 and human CLICs have conserved functions in tubulogenesis, and CLICs and Gα-Rho/Rac signaling regulate tubulogenesis during blood vessel development. Therefore, our work defines a primordial role for EXC-4/CLICs in Gα-Rho/Rac-signaling during tubulogenesis.

scholarly journals The RFamide receptor DMSR-1 regulates stress-induced sleep in C. elegans

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Michael J Iannacone ◽  
Isabel Beets ◽  
Lindsey E Lopes ◽  
Matthew A Churgin ◽  
Christopher Fang-Yen ◽  
...  
Keyword(s):  
Cell Culture ◽  
G Protein ◽  
Behavioral Response ◽  
Genetic Screen ◽  
Sleep Behavior ◽  
C Elegans ◽  
Cytokine Activation ◽  
C Terminus ◽  
G Protein Coupled

In response to environments that cause cellular stress, animals engage in sleep behavior that facilitates recovery from the stress. In Caenorhabditis elegans, stress-induced sleep(SIS) is regulated by cytokine activation of the ALA neuron, which releases FLP-13 neuropeptides characterized by an amidated arginine-phenylalanine (RFamide) C-terminus motif. By performing an unbiased genetic screen for mutants that impair the somnogenic effects of FLP-13 neuropeptides, we identified the gene dmsr-1, which encodes a G-protein coupled receptor similar to an insect RFamide receptor. DMSR-1 is activated by FLP-13 peptides in cell culture, is required for SIS in vivo, is expressed non-synaptically in several wake-promoting neurons, and likely couples to a Gi/o heterotrimeric G-protein. Our data expand our understanding of how a single neuroendocrine cell coordinates an organism-wide behavioral response, and suggest that similar signaling principles may function in other organisms to regulate sleep during sickness.

scholarly journals Rgs4 is a regulator of mTOR activity required for motoneuron axon outgrowth and neuronal development in zebrafish

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aya Mikdache ◽  
Marie-José Boueid ◽  
Lorijn van der Spek ◽  
Emilie Lesport ◽  
Brigitte Delespierre ◽  
...  
Keyword(s):  
Nervous System ◽  
G Protein ◽  
Neural Development ◽  
Neuronal Development ◽  
Axon Outgrowth ◽  
Rgs Proteins ◽  
Protein Signaling ◽  
Loss Of Function ◽  
G Protein Coupled

AbstractThe Regulator of G protein signaling 4 (Rgs4) is a member of the RGS proteins superfamily that modulates the activity of G-protein coupled receptors. It is mainly expressed in the nervous system and is linked to several neuronal signaling pathways; however, its role in neural development in vivo remains inconclusive. Here, we generated and characterized a rgs4 loss of function model (MZrgs4) in zebrafish. MZrgs4 embryos showed motility defects and presented reduced head and eye sizes, reflecting defective motoneurons axon outgrowth and a significant decrease in the number of neurons in the central and peripheral nervous system. Forcing the expression of Rgs4 specifically within motoneurons rescued their early defective outgrowth in MZrgs4 embryos, indicating an autonomous role for Rgs4 in motoneurons. We also analyzed the role of Akt, Erk and mechanistic target of rapamycin (mTOR) signaling cascades and showed a requirement for these pathways in motoneurons axon outgrowth and neuronal development. Drawing on pharmacological and rescue experiments in MZrgs4, we provide evidence that Rgs4 facilitates signaling mediated by Akt, Erk and mTOR in order to drive axon outgrowth in motoneurons and regulate neuronal numbers.

scholarly journals Functional expression and characterization of the C. elegans G-protein-coupled FLP-2 Receptor (T19F4.1) in mammalian cells and yeast

2013 ◽  
Vol 3 ◽  
pp. 1-7 ◽  
Author(s):  
Martha J. Larsen ◽  
Elizabeth Ruiz Lancheros ◽  
Tracey Williams ◽  
David E. Lowery ◽  
Timothy G. Geary ◽  
...  
Keyword(s):  
G Protein ◽  
Mammalian Cells ◽  
Functional Expression ◽  
C Elegans ◽  
G Protein Coupled

scholarly journals G Proteins and GPCRs in C. elegans Development: A Story of Mutual Infidelity

2018 ◽  
Vol 6 (4) ◽  
pp. 28 ◽  
Author(s):  
Daniel Matúš ◽  
Simone Prömel
Keyword(s):  
Signaling Pathways ◽  
G Protein ◽  
G Proteins ◽  
Cell Polarity ◽  
Protein Activity ◽  
Independent Manner ◽  
C Elegans ◽  
Downstream Effectors ◽  
Complex Signaling ◽  
G Protein Coupled

Many vital processes during C. elegans development, especially the establishment and maintenance of cell polarity in embryogenesis, are controlled by complex signaling pathways. G protein-coupled receptors (GPCRs), such as the four Frizzled family Wnt receptors, are linchpins in regulating and orchestrating several of these mechanisms. However, despite being GPCRs, which usually couple to G proteins, these receptors do not seem to activate classical heterotrimeric G protein-mediated signaling cascades. The view on signaling during embryogenesis is further complicated by the fact that heterotrimeric G proteins do play essential roles in cell polarity during embryogenesis, but their activity is modulated in a predominantly GPCR-independent manner via G protein regulators such as GEFs GAPs and GDIs. Further, the triggered downstream effectors are not typical. Only very few GPCR-dependent and G protein-mediated signaling pathways have been unambiguously defined in this context. This unusual and highly intriguing concept of separating GPCR function and G-protein activity, which is not restricted to embryogenesis in C. elegans but can also be found in other organisms, allows for essential and multi-faceted ways of regulating cellular communication and response. Although its relevance cannot be debated, its impact is still poorly discussed, and C. elegans is an ideal model to understand the underlying principles.

scholarly journals Yeast-Based Directed-Evolution For High-Throughput Structural Stabilization of G Protein-Coupled Receptors (GPCRs)

2021 ◽  
Author(s):  
May Meltzer ◽  
Zvagelsky Tatiana ◽  
Niv Papo ◽  
Stanislav Engel
Keyword(s):  
G Protein ◽  
Resistant Cell ◽  
Single Step ◽  
G Protein Coupled Receptors ◽  
Structural Basis ◽  
Diffusion Method ◽  
Structural Stabilization ◽  
C Terminus ◽  
Screening Platform ◽  
G Protein Coupled

Abstract The immense potential of G protein-coupled receptors (GPCRs) as targets for drug discovery is not fully realized due to the enormous difficulties associated with structure elucidation of these profoundly unstable membrane proteins. The existing methods of GPCR stability-engineering are cumbersome and low-throughput; in addition, the scope of GPCRs that could benefit from these techniques is limited. Here, we presented a yeast-based screening platform for a single-step isolation of GRCR variants stable in the presence of short-chain detergents, a feature essential for their successful crystallization using vapor diffusion method. The detergent-resistant cell wall of yeast provides a unique compartmentalization opportunity to physically link the receptor phenotype to its encoding DNA, and thus enable discovery of stable GPCR variants with unprecedent efficiency. The scope of mutations identified by the method offers important insights into the structural basis of GPCR stability, questioning the inherent instability of the GPCR scaffold, and revealing the potential role of the C-terminus in receptor stabilization.

scholarly journals Novel fluorescent GPCR biosensor detects retinal equilibrium binding to opsin and active G protein and arrestin signaling conformations

2020 ◽  
Vol 295 (51) ◽  
pp. 17486-17496
Author(s):  
Christopher T. Schafer ◽  
Anthony Shumate ◽  
David L. Farrens
Keyword(s):  
G Protein ◽  
Protein Activation ◽  
Canonical Class ◽  
Equilibrium Binding ◽  
C Terminus ◽  
G Protein Activation ◽  
Ligand Discovery ◽  
Pharmaceutical Agents ◽  
G Protein Coupled ◽  
Covalently Bound

Rhodopsin is a canonical class A photosensitive G protein–coupled receptor (GPCR), yet relatively few pharmaceutical agents targeting this visual receptor have been identified, in part due to the unique characteristics of its light-sensitive, covalently bound retinal ligands. Rhodopsin becomes activated when light isomerizes 11-cis-retinal into an agonist, all-trans-retinal (ATR), which enables the receptor to activate its G protein. We have previously demonstrated that, despite being covalently bound, ATR can display properties of equilibrium binding, yet how this is accomplished is unknown. Here, we describe a new approach for both identifying compounds that can activate and attenuate rhodopsin and testing the hypothesis that opsin binds retinal in equilibrium. Our method uses opsin-based fluorescent sensors, which directly report the formation of active receptor conformations by detecting the binding of G protein or arrestin fragments that have been fused onto the receptor's C terminus. We show that these biosensors can be used to monitor equilibrium binding of the agonist, ATR, as well as the noncovalent binding of β-ionone, an antagonist for G protein activation. Finally, we use these novel biosensors to observe ATR release from an activated, unlabeled receptor and its subsequent transfer to the sensor in real time. Taken together, these data support the retinal equilibrium binding hypothesis. The approach we describe should prove directly translatable to other GPCRs, providing a new tool for ligand discovery and mutant characterization.

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