scholarly journals Brassinosteroid signal transduction from cell-surface receptor kinases to nuclear transcription factors

2009 ◽  
Vol 11 (10) ◽  
pp. 1254-1260 ◽  
Author(s):  
Tae-Wuk Kim ◽  
Shenheng Guan ◽  
Yu Sun ◽  
Zhiping Deng ◽  
Wenqiang Tang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Transcription Factors ◽  
Cell Surface ◽  
Cell Surface Receptor ◽  
Receptor Kinases ◽  
Surface Receptor

scholarly journals Constitutive Activation and Inactivation of Mutations Inducing Cell Surface Loss of Receptor and Impairing of Signal Transduction of Agonist-Stimulated Eel Follicle-Stimulating Hormone Receptor

2020 ◽  
Vol 21 (19) ◽  
pp. 7075
Author(s):  
Munkhzaya Byambaragchaa ◽  
Jeong-Soo Kim ◽  
Hong-Kyu Park ◽  
Dae-Jung Kim ◽  
Sun-Mee Hong ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Surface ◽  
Hormone Receptor ◽  
Follicle Stimulating Hormone ◽  
Chinese Hamster ◽  
Cell Surface Receptor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Wild Type ◽  
Surface Receptor ◽  
Stimulating Hormone

In the present study, we investigated the signal transduction of mutants of the eel follicle-stimulating hormone receptor (eelFSHR). Specifically, we examined the constitutively activating mutant D540G in the third intracellular loop, and four inactivating mutants (A193V, N195I, R546C, and A548V). To directly assess functional effects, we conducted site-directed mutagenesis to generate mutant receptors. We measured cyclic adenosine monophosphate (cAMP) accumulation via homogeneous time-resolved fluorescence assays in Chinese hamster ovary (CHO-K1) cells and investigated cell surface receptor loss using an enzyme-linked immunosorbent assay in human embryonic kidney (HEK) 293 cells. The cells expressing eelFSHR-D540G exhibited a 23-fold increase in the basal cAMP response without agonist treatment. The cells expressing A193V, N195I, and A548V mutants had completely impaired signal transduction, whereas those expressing the R546C mutant exhibited little increase in cAMP responsiveness and a small increase in signal transduction. Cell surface receptor loss in the cells expressing inactivating mutants A193V, R546C, and A548V was clearly slower than in the cell expressing the wild-type eelFSHR. However, cell surface receptor loss in the cells expressing inactivating mutant N195I decreased in a similar manner to that of the cells expressing the wild-type eelFSHR or the activating mutant D540G, despite the completely impaired cAMP response. These results provide important information regarding the structure–function relationships of G protein-coupled receptors during signal transduction.

scholarly journals Constitutively Activating Mutants of Equine LH/CGR Constitutively Induce Signal Transduction and Inactivating Mutations Impair Biological Activity and Cell-Surface Receptor Loss In Vitro

2021 ◽  
Vol 22 (19) ◽  
pp. 10723
Author(s):  
Munkhzaya Byambaragchaa ◽  
Hoon-Ki Seong ◽  
Seung-Hee Choi ◽  
Dae-Jung Kim ◽  
Myung-Hwa Kang ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Surface ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Adenosine Monophosphate ◽  
Cell Surface Receptor ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Concentration ◽  
Surface Receptor

The signal transduction of the equine lutropin/choriogonadotropin receptor (eLH/CGR) is unclear in naturally occurring activating/inactivating mutants of this receptor, which plays an important role in reproductive physiology. We undertook the present study to determine whether conserved structurally related mutations in eLH/CGR exhibit similar mechanisms of signal transduction. We constructed four constitutively activating mutants (M398T, L457R, D564G, and D578Y) and three inactivating mutants (D405N, R464H, and Y546F); measured cyclic adenosine monophosphate (cAMP) accumulation via homogeneous time-resolved fluorescence assays in Chinese hamster ovary cells; and investigated cell-surface receptor loss using an enzyme-linked immunosorbent assay in human embryonic kidney 293 cells. The eLH/CGR-L457R-, -D564G-, and -D578Y-expressing cells exhibited 16.9-, 16.4-, and 11.2-fold increases in basal cAMP response, respectively. The eLH/CGR-D405N- and R464H-expressing cells presented a completely impaired signal transduction, whereas the Y546F-expressing cells exhibited a small increase in cAMP response. The cell-surface receptor loss was 1.4- to 2.4-fold greater in the activating-mutant-expressing cells than in wild-type eLH/CGR-expressing cells, but was completely impaired in the D405N- and Y546F-expressing cells, despite treatment with a high concentration of agonist. In summary, the state of activation of eLH/CGR influenced agonist-induced cell-surface receptor loss, which was directly related to the signal transduction of constitutively activating mutants.

Mutations in the WSAWSE and cytosolic domains of the erythropoietin receptor affect signal transduction and ligand binding and internalization

1992 ◽  
Vol 12 (10) ◽  
pp. 4553-4561
Author(s):  
D E Quelle ◽  
F W Quelle ◽  
D M Wojchowski
Keyword(s):  
Signal Transduction ◽  
Cell Surface ◽  
Ligand Binding ◽  
Erythropoietin Receptor ◽  
Cell Surface Receptor ◽  
Erythroid Progenitor ◽  
Epo Receptor ◽  
Cytosolic Domain ◽  
Cytosolic Domains ◽  
Surface Receptor

The terminal development of erythroid progenitor cells is promoted in part through the interaction of erythropoietin (EPO) with its cell surface receptor. This receptor and a growing family of related cytokine receptors share homologous extracellular features, including a well-conserved WSXWS motif. To explore the functional significance of this motif in the murine EPO receptor, five WSAWSE mutants were prepared and their signal-transducing, ligand binding, and endocytotic properties were compared. EPO receptors mutated at tryptophan residues (W-232, W-235----G; W-235----G; W-235----F) failed to mediate EPO-induced growth or pp100 phosphorylation, while S-236----T and E-237----K mutants exhibited partial to full activity (50 to 100% of wild-type growth and induced phosphorylation). Ligand affinity was reduced for mutant receptors (two- to fivefold), yet expression at the cell surface for all receptors was nearly equivalent. Also, the ability of mutated receptors to internalize ligand was either markedly reduced or abolished (W-235----F), indicating a role for the WSAWSE region in hormone internalization. Interestingly, receptor forms lacking 97% of the cytosolic domain (no signal-transducing capacity; binding affinity reduced two- to threefold) internalized EPO efficiently. This and all WSAWSE receptor forms studied also mediated specific cross-linking of 125I-EPO to three accessory membrane proteins (M(r)s, 120,000, 105,000, and 93,000). These findings suggest that the WSAWSE domain of the EPO receptor is important for EPO-induced signal transduction and ligand internalization. In contrast, although the cytosolic domain is required for growth signaling, it appears nonessential for efficient endocytosis.

scholarly journals Mutations in the WSAWSE and cytosolic domains of the erythropoietin receptor affect signal transduction and ligand binding and internalization.

1992 ◽  
Vol 12 (10) ◽  
pp. 4553-4561 ◽  
Author(s):  
D E Quelle ◽  
F W Quelle ◽  
D M Wojchowski
Keyword(s):  
Signal Transduction ◽  
Cell Surface ◽  
Ligand Binding ◽  
Erythropoietin Receptor ◽  
Cell Surface Receptor ◽  
Erythroid Progenitor ◽  
Epo Receptor ◽  
Cytosolic Domain ◽  
Cytosolic Domains ◽  
Surface Receptor

The terminal development of erythroid progenitor cells is promoted in part through the interaction of erythropoietin (EPO) with its cell surface receptor. This receptor and a growing family of related cytokine receptors share homologous extracellular features, including a well-conserved WSXWS motif. To explore the functional significance of this motif in the murine EPO receptor, five WSAWSE mutants were prepared and their signal-transducing, ligand binding, and endocytotic properties were compared. EPO receptors mutated at tryptophan residues (W-232, W-235----G; W-235----G; W-235----F) failed to mediate EPO-induced growth or pp100 phosphorylation, while S-236----T and E-237----K mutants exhibited partial to full activity (50 to 100% of wild-type growth and induced phosphorylation). Ligand affinity was reduced for mutant receptors (two- to fivefold), yet expression at the cell surface for all receptors was nearly equivalent. Also, the ability of mutated receptors to internalize ligand was either markedly reduced or abolished (W-235----F), indicating a role for the WSAWSE region in hormone internalization. Interestingly, receptor forms lacking 97% of the cytosolic domain (no signal-transducing capacity; binding affinity reduced two- to threefold) internalized EPO efficiently. This and all WSAWSE receptor forms studied also mediated specific cross-linking of 125I-EPO to three accessory membrane proteins (M(r)s, 120,000, 105,000, and 93,000). These findings suggest that the WSAWSE domain of the EPO receptor is important for EPO-induced signal transduction and ligand internalization. In contrast, although the cytosolic domain is required for growth signaling, it appears nonessential for efficient endocytosis.

Sign in / Sign up

Export Citation Format

Share Document