Site of G protein binding to rhodopsin mapped with synthetic peptides from the alpha subunit

Science ◽  
1988 ◽  
Vol 241 (4867) ◽  
pp. 832-835 ◽  
Author(s):  
H. Hamm ◽  
D Deretic ◽  
A Arendt ◽  
P. Hargrave ◽  
B Koenig ◽  
...  
Keyword(s):  
Protein Binding ◽  
G Protein ◽  
Synthetic Peptides ◽  
Alpha Subunit

scholarly journals G-Protein binding domains of the angiotensin II AT1A receptors mapped with synthetic peptides selected from the receptor sequence

1998 ◽  
Vol 332 (3) ◽  
pp. 781-787 ◽  
Author(s):  
Hisashi KAI ◽  
R. Wayne ALEXANDER ◽  
Masuko USHIO-FUKAI ◽  
P. Reid LYONS ◽  
Marjorie AKERS ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Protein Binding ◽  
G Protein ◽  
G Proteins ◽  
Synthetic Peptides ◽  
Terminal Region ◽  
Functional Coupling ◽  
Intracellular Loop ◽  
Binding Domains ◽  
Gtpase Activation

The vascular angiotensin II type 1 receptor (AT1AR) is a member of the G-protein-coupled receptor superfamily. We mapped the G-protein binding domains of the AT1AR using synthetic peptides selected from the receptor sequence, which interfere with AT1AR–G-protein coupling. Membrane GTPase activity was used as a measure of the functional coupling in rat vascular smooth muscle cells. Peptides corresponding to the N-terminal region of the second intracellular loop (residues 125–137), the N-terminal region of the third intracellular loop (217–227) and the juxtamembranous region of the C-terminal tail (304–316) inhibited angiotensin II-induced GTPase activation by 30%, 30%, and 70%, respectively. The latter two domains (217–227 and 304–316) are predicted to form amphiphilic α-helices. Only the peptide representing residues 217–227 stimulated basal activity (45%). No synthetic peptide had a significant effect on either the number or the affinity of the AT1AR binding. These observations indicate that domains of the second and third regions and the cytoplasmic tail of the AT1AR interact with G-proteins, and that multiple contacts with these receptor domains may be important for binding and activation of the G-proteins.

Transient Prealbumin- Associated Hyperthyroxinemia in TSH-Producing Pituitary Adenoma

1990 ◽  
Vol 29 (01) ◽  
pp. 40-43 ◽  
Author(s):  
W. Langsteger ◽  
P. Költringer ◽  
P. Wakonig ◽  
B. Eber ◽  
M. Mokry ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Case Report ◽  
Pituitary Adenoma ◽  
Thyroid Hormones ◽  
Protein Binding ◽  
Alpha Subunit ◽  
Normal Range ◽  
Thyroxine Binding Globulin ◽  
Free Thyroid Hormones ◽  
Transmission Computed Tomography

This case report describes a 38-year-old male who was hospitalized for further clarification of clinically mild hyperthyroidism. His increased total hormone levels, the elevated free thyroid hormones and the elevated basal TSH with blunted response to TRH strongly suggested a pituitary adenoma with inappropriate TSH incretion. Transmission computed tomography showed an intrasellar expansion, 16 mm in diameter. The neoplastic TSH production was confirmed by an elevated alpha-subunit and a raised molar alpha-sub/ATSH ratio. However, T4 distribution on prealbumin (PA, TTR), albumin (A) and thyroxine binding globulin (TBG) showed a clearly increased binding to PA (39%), indicating additional prealbumin-associated hyperthyroxinemia. The absolute values of PA, A and TBG were within the normal range. After removal of the TSH-producing adenoma, basal TSH, the free thyroid hormones and T4 binding to prealbumin returned to normal. Therefore, the prealbumin-associated hyperthyroxinemia had to be interpreted as a transitory phenomenon related to secondary hyperthyroidism (T4 shift from thyroxine binding globulin to prealbumin) rather than a genetically conditioned anomaly of protein binding.

scholarly journals A long isoform of GIV/Girdin contains a PDZ binding module that regulates localization and G-protein binding

2021 ◽  
pp. 100493
Author(s):  
Jason Ear ◽  
Amer Ali Abd El-Hafeez ◽  
Suchismita Roy ◽  
Tony Ngo ◽  
Navin Rajapakse ◽  
...  
Keyword(s):  
Protein Binding ◽  
G Protein
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