G-protein-coupled receptors and localized signaling in the primary cilium during ventral neural tube patterning

2014 ◽  
Vol 103 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Sun-Hee Hwang ◽  
Saikat Mukhopadhyay
Keyword(s):  
G Protein ◽  
Neural Tube ◽  
Primary Cilium ◽  
G Protein Coupled Receptors ◽  
Ventral Neural Tube ◽  
G Protein Coupled

Analysis of ciliary status via G-protein-coupled receptors localized on primary cilia

Microscopy ◽  
2020 ◽  
Vol 69 (5) ◽  
pp. 277-285
Author(s):  
Yuki Kobayashi ◽  
Akie Hamamoto ◽  
Yumiko Saito
Keyword(s):  
G Protein ◽  
Primary Cilium ◽  
Somatostatin Receptor ◽  
G Protein Coupled Receptors ◽  
The Body ◽  
Cell Surface Receptor ◽  
Specific Cell ◽  
Gpcr Signaling ◽  
Sequence Of Events ◽  
G Protein Coupled

Abstract G-protein-coupled receptors (GPCRs) comprise the largest and most diverse cell surface receptor family, with more than 800 known GPCRs identified in the human genome. Binding of an extracellular cue to a GPCR results in intracellular G protein activation, after which a sequence of events, can be amplified and optimized by selective binding partners and downstream effectors in spatially discrete cellular environments. Because GPCRs are widely expressed in the body, they help to regulate an incredible range of physiological processes from sensation to growth to hormone responses. Indeed, it is estimated that ∼ 30% of all clinically approved drugs act by binding to GPCRs. The primary cilium is a sensory organelle composed of a microtubule axoneme that extends from the basal body. The ciliary membrane is highly enriched in specific signaling components, allowing the primary cilium to efficiently convey signaling cascades in a highly ordered microenvironment. Recent data demonstrated that a limited number of non-olfactory GPCRs, including somatostatin receptor 3 and melanin-concentrating hormone receptor 1 (MCHR1), are selectively localized to cilia on several mammalian cell types including neuronal cells. Utilizing cilia-specific cell biological and molecular biological approaches, evidence has accumulated to support the biological importance of ciliary GPCR signaling followed by cilia structural changes. Thus, cilia are now considered a unique sensory platform for integration of GPCR signaling toward juxtaposed cytoplasmic structures. Herein, we review ciliary GPCRs and focus on a novel role of MCHR1 in ciliary length control that will impact ciliary signaling capacity and neuronal function.

scholarly journals The Ciliary Lumen Accommodates Passive Diffusion and Vesicle Trafficking in Cytoplasmic-Ciliary Transport

2019 ◽  
Author(s):  
Andrew Ruba ◽  
Wangxi Luo ◽  
Jingjie Yu ◽  
Daisuke Takao ◽  
Athanasios Evangelou ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
G Protein ◽  
Single Molecule ◽  
Primary Cilium ◽  
Intraflagellar Transport ◽  
Vesicle Transport ◽  
Passive Diffusion ◽  
G Protein Coupled Receptors ◽  
Live Cells ◽  
G Protein Coupled

AbstractTransport of membrane and cytosolic proteins into the primary cilium is essential for its role in cellular signaling. Using single molecule microscopy, we mapped the movement of membrane and soluble proteins at the base of the primary cilium. In addition to the well-known intraflagellar transport (IFT) route, we identified two new pathways within the lumen of the primary cilium - passive diffusional and vesicle transport routes - that are adopted by proteins for cytoplasmic-cilium transport in live cells. Independent of the IFT path, approximately half of IFT motors (KIF3A) and cargo (α-tubulin) take the passive diffusion route and more than half of membrane-embedded G protein coupled receptors (SSTR3 and HTR6) use RAB8A-regulated vesicles to transport into and inside cilia. Furthermore, ciliary lumen transport is the preferred route for membrane proteins in the early stages of ciliogenesis and inhibition of SSTR3 vesicle transport completely blocks ciliogenesis. Furthermore, clathrin-mediated, signal-dependent internalization of SSTR3 also occurs through the ciliary lumen. These transport routes were also observed in Chlamydomonas reinhardtii flagella, suggesting their conserved roles in trafficking of ciliary proteins.

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