The G Protein Cascade of Visual Transduction: Kinetics and Regulation

2007 ◽  
pp. 112-127 ◽  
Author(s):  
Marc Chabre ◽  
Bruno Antonny ◽  
Franz Bruckert And ◽  
T. Minh Vuong
Keyword(s):  
G Protein ◽  
Visual Transduction

scholarly journals Effects of carboxyl methylation of photoreceptor G protein gamma-subunit in visual transduction.

1994 ◽  
Vol 269 (7) ◽  
pp. 5163-5170
Author(s):  
Y. Fukada ◽  
T. Matsuda ◽  
K. Kokame ◽  
T. Takao ◽  
Y. Shimonishi ◽  
...  
Keyword(s):  
G Protein ◽  
Visual Transduction ◽  
Gamma Subunit ◽  
Carboxyl Methylation

Deactivation of visual transduction without guanosine triphosphate hydrolysis by G protein

Science ◽  
1992 ◽  
Vol 257 (5074) ◽  
pp. 1255-1258 ◽  
Author(s):  
M. Erickson ◽  
P Robinson ◽  
J Lisman
Keyword(s):  
G Protein ◽  
Guanosine Triphosphate ◽  
Visual Transduction

The structure of bacteriorhodopsin and its relevance to the visual opsins and other seven-helix G-protein coupled receptors

1990 ◽  
Vol 326 (1236) ◽  
pp. 379-389 ◽  
Keyword(s):  
G Protein ◽  
Chloride Ion ◽  
G Protein Coupled Receptors ◽  
Three Dimensions ◽  
Ion Pump ◽  
Direct Sequence ◽  
Transmembrane Helices ◽  
Visual Transduction ◽  
Receptor Proteins ◽  
G Protein Coupled

Bacteriorhodopsin is a light-driven hydrogen-ion pump whose structure is known to about 6.0 Å in three dimensions and 2.8 Å in projection. It consists of seven transmembrane helices surrounding the chromophore, retinal. Halorhodopsin is a second member of the same family of membrane proteins, both of them from the cell membrane of halobacteria. Halorhodopsin is a light-driven chloride-ion pump but has very close homology to bacteriorhodopsin, especially around the retinal. In contrast, the visual opsins that are responsible for the primary step in visual transduction in all eukaryotes from Drosophila upwards, form a separate family with no direct sequence homology to the bacteriorhodopsin family. The visual opsin family now includes about 15 other receptor proteins, all of which activate G-protein cascades, including the β-adrenergic receptor as well as several others. Despite the lack of clear relations at the level of amino acid sequence, there are topographical similarities between the bacteriorhodopsin and the visual opsin families in the nature and site of chromophore attachment, the number of transmembrane helices and the positions of the amino and carboxyl termini in the membrane. These suggest that if the two were at one time closely related, they have diverged too far to have sequences that are detectably similar.

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

A compendium of G-protein–coupled receptors and cyclic nucleotide regulation of adipose tissue metabolism and energy expenditure

2020 ◽  
Vol 134 (5) ◽  
pp. 473-512 ◽  
Author(s):  
Ryan P. Ceddia ◽  
Sheila Collins
Keyword(s):  
Adipose Tissue ◽  
Energy Expenditure ◽  
Signaling Pathways ◽  
G Protein ◽  
Uncoupling Protein ◽  
Beige Adipocytes ◽  
Nucleotide Regulation ◽  
Ucp1 Expression ◽  
Thermogenic Adipocytes ◽  
G Protein Coupled

Abstract With the ever-increasing burden of obesity and Type 2 diabetes, it is generally acknowledged that there remains a need for developing new therapeutics. One potential mechanism to combat obesity is to raise energy expenditure via increasing the amount of uncoupled respiration from the mitochondria-rich brown and beige adipocytes. With the recent appreciation of thermogenic adipocytes in humans, much effort is being made to elucidate the signaling pathways that regulate the browning of adipose tissue. In this review, we focus on the ligand–receptor signaling pathways that influence the cyclic nucleotides, cAMP and cGMP, in adipocytes. We chose to focus on G-protein–coupled receptor (GPCR), guanylyl cyclase and phosphodiesterase regulation of adipocytes because they are the targets of a large proportion of all currently available therapeutics. Furthermore, there is a large overlap in their signaling pathways, as signaling events that raise cAMP or cGMP generally increase adipocyte lipolysis and cause changes that are commonly referred to as browning: increasing mitochondrial biogenesis, uncoupling protein 1 (UCP1) expression and respiration.

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