Gu Q, Ding YS, Zhang TL (May 2010). "Prediction of G-protein-coupled receptor classes in low homology using Chou's pseudo amino acid composition with approximate entropy and hydrophobicity patterns". Protein and Peptide Letters. 17 (5): 559–67. doi: 10.2174/092986610791112693. PMID 19594431. One other disadvantage is that vertical curves as when entering or leaving a grade, will move the couplers up and down significantly on long cars. Your vertical transitions cannot be sharp like a roller coaster. "Standard" body mount couplers: Although they are classically thought of working only together, GPCRs may signal through G-protein-independent mechanisms, and heterotrimeric G-proteins may play functional roles independent of GPCRs. GPCRs may signal independently through many proteins already mentioned for their roles in G-protein-dependent signaling such as β-arrs, GRKs, and Srcs. Such signaling has been shown to be physiologically relevant, for example, β-arrestin signaling mediated by the chemokine receptor CXCR3 was necessary for full efficacy chemotaxis of activated T cells. [49] In addition, further scaffolding proteins involved in subcellular localization of GPCRs (e.g., PDZ-domain-containing proteins) may also act as signal transducers. Most often the effector is a member of the MAPK family. Xu F, Wu H, Katritch V, Han GW, Jacobson KA, Gao ZG, etal. (April 2011). "Structure of an agonist-bound human A2A adenosine receptor". Science. 332 (6027): 322–7. Bibcode: 2011Sci...332..322X. doi: 10.1126/science.1202793. PMC 3086811. PMID 21393508.

The G protein-coupled receptor kinases (GRKs) are protein kinases that phosphorylate only active GPCRs. [54] G-protein-coupled receptor kinases (GRKs) are key modulators of G-protein-coupled receptor (GPCR) signaling. They constitute a family of seven mammalian serine-threonine protein kinases that phosphorylate agonist-bound receptor. GRKs-mediated receptor phosphorylation rapidly initiates profound impairment of receptor signaling and desensitization. Activity of GRKs and subcellular targeting is tightly regulated by interaction with receptor domains, G protein subunits, lipids, anchoring proteins and calcium-sensitive proteins. [55] keyword:"G-protein coupled receptor [KW-0297]" AND organism:"Homo sapiens (Human) [9606]" in UniProtKB". www.uniprot.org. Archived from the original on 15 September 2020 . Retrieved 24 June 2019. a b c Bjarnadóttir TK, Gloriam DE, Hellstrand SH, Kristiansson H, Fredriksson R, Schiöth HB (September 2006). "Comprehensive repertoire and phylogenetic analysis of the G protein-coupled receptors in human and mouse". Genomics. 88 (3): 263–73. doi: 10.1016/j.ygeno.2006.04.001. PMID 16753280. The "#1 Scale" centerset coupler from the Kadee 1907 kit is evaluated for installation in both Datum Precision Metal Coupler Box and 3-D printed plastic "CamPac Box TM". Various couplers are included in the illustrations that follow.lipid mediators of inflammation (e.g., prostaglandins, prostanoids, platelet-activating factor, and leukotrienes);

Illustrated below is a side by side comparison of the GP38 fitted with couplers from Kadee kits 907 and 1907. The Nobel Prize in Chemistry 2012" (PDF). Archived (PDF) from the original on 18 October 2012 . Retrieved 10 October 2012. In that vignette an example Kadee 880 gauge coupler height measured 1.115 inches from the rail head surface (or 32.33 inches if scaled up to prototype 1/1) - thus, the Kadee gauge is within the prototype allowance with respect to CFR 49, section 232.2 - it being somewhat below the center of the CFR range of 33 inches.

"Standard" body mount couplers:

In the late 1990s, evidence began accumulating to suggest that some GPCRs are able to signal without G proteins. The ERK2 mitogen-activated protein kinase, a key signal transduction mediator downstream of receptor activation in many pathways, has been shown to be activated in response to cAMP-mediated receptor activation in the slime mold D. discoideum despite the absence of the associated G protein α- and β-subunits. [50] Below is the loco originally equipped with the coupler from the 907 coupled with the 907 of the same tank car. The centers of these couplers line up. Vassilatis DK, Hohmann JG, Zeng H, Li F, Ranchalis JE, Mortrud MT, etal. (April 2003). "The G protein-coupled receptor repertoires of human and mouse". Proceedings of the National Academy of Sciences of the United States of America. 100 (8): 4903–8. Bibcode: 2003PNAS..100.4903V. doi: 10.1073/pnas.0230374100. PMC 153653. PMID 12679517.

According to the classical A-F system, GPCRs can be grouped into 6 classes based on sequence homology and functional similarity: [13] [14] [15] [16] Venkatakrishnan AJ, Deupi X, Lebon G, Tate CG, Schertler GF, Babu MM (February 2013). "Molecular signatures of G-protein-coupled receptors". Nature. 494 (7436): 185–94. Bibcode: 2013Natur.494..185V. doi: 10.1038/nature11896. PMID 23407534. S2CID 4423750. Joost P, Methner A (October 2002). "Phylogenetic analysis of 277 human G-protein-coupled receptors as a tool for the prediction of orphan receptor ligands". Genome Biology. 3 (11): RESEARCH0063. doi: 10.1186/gb-2002-3-11-research0063. PMC 133447. PMID 12429062. KeyKeg Coupler- This is becoming one of the more common types of keg coupler in the UK, particularly in smaller outlets like Micropubs and restaurant bars to serve small batch ales. Designed for use with one way disposable beer containers.

S Type Sankey Keg Coupler

Adenylyl cyclase is a 12-transmembrane glycoprotein that catalyzes the conversion of ATP to cAMP with the help of cofactor Mg 2+ or Mn 2+. The cAMP produced is a second messenger in cellular metabolism and is an allosteric activator of protein kinase A.

It's intended that the Datum Precision coupler box is to accept a Kadee centerset coupler (e.g. having no up or down offset - coupler from the Kadee 789 or 907 kits) for mounting on the Aristo-Craft GP40 and other applications. The initial intended use was for the Aristo-Craft GP40 and SD45 diesel locos - but from the onset the boxes were, also, configured for potential applications on others.

G Type Grundy Keg Coupler

G protein-coupled receptors are found only in eukaryotes, including yeast, and choanoflagellates. [4] The ligands that bind and activate these receptors include light-sensitive compounds, odors, pheromones, hormones, and neurotransmitters, and vary in size from small molecules to peptides to large proteins. G protein-coupled receptors are involved in many diseases. There are three main G-protein-mediated signaling pathways, mediated by four sub-classes of G-proteins distinguished from each other by sequence homology ( G αs, G αi/o, G αq/11, and G α12/13). Each sub-class of G-protein consists of multiple proteins, each the product of multiple genes or splice variations that may imbue them with differences ranging from subtle to distinct with regard to signaling properties, but in general they appear reasonably grouped into four classes. Because the signal transducing properties of the various possible βγ combinations do not appear to radically differ from one another, these classes are defined according to the isoform of their α-subunit. [6] :1163 Saroz Y, Kho DT, Glass M, Graham ES, Grimsey NL (December 2019). "Cannabinoid Receptor 2 (CB 2) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes". ACS Pharmacology & Translational Science. 2 (6): 414–428. doi: 10.1021/acsptsci.9b00049. PMC 7088898. PMID 32259074. In mammalian cells, the much-studied β 2-adrenoceptor has been demonstrated to activate the ERK2 pathway after arrestin-mediated uncoupling of G-protein-mediated signaling. Therefore, it seems likely that some mechanisms previously believed related purely to receptor desensitisation are actually examples of receptors switching their signaling pathway, rather than simply being switched off.