Skip to content

Commit

Permalink
errata 24215
Browse files Browse the repository at this point in the history
  • Loading branch information
oscryan committed Mar 15, 2024
1 parent e9c1ef2 commit e6f780b
Show file tree
Hide file tree
Showing 2 changed files with 2 additions and 2 deletions.
2 changes: 1 addition & 1 deletion modules/m62798/index.cnxml
Original file line number Diff line number Diff line change
Expand Up @@ -175,7 +175,7 @@
</media>
<caption>Gated ion channels form a pore through the plasma membrane that opens when the signaling molecule binds. The open pore then allows ions to flow into or out of the cell.</caption></figure><para id="fs-id2592121"><term id="term-00019">G-protein-linked receptors</term> bind a ligand and activate a membrane protein called a G-protein. The activated G-protein then interacts with either an ion channel or an enzyme in the membrane (<link target-id="fig-ch09_01_05"/>). All G-protein-linked receptors have seven transmembrane domains, but each receptor has its own specific extracellular domain and G-protein-binding site.</para>
<para id="fs-id2336863">Cell signaling using G-protein-linked receptors occurs as a cyclic series of events. Before the ligand binds, the inactive G-protein can bind to a newly revealed site on the receptor specific for its binding. Once the signaling molecule binds to the receptor, the resultant shape change activates the G-protein, which releases GDP and picks up GTP. The subunits of the G-protein then split into the <emphasis effect="italics">α</emphasis> subunit and the <emphasis effect="italics">βγ</emphasis> subunit. One or both of these G-protein fragments may be able to activate other proteins as a result. After awhile, the GTP on the active <emphasis effect="italics">α</emphasis> subunit of the G-protein is hydrolyzed to GDP and the <emphasis effect="italics">βγ</emphasis> subunit is deactivated. The subunits reassociate to form the inactive G-protein and the cycle begins anew.</para>
<figure id="fig-ch09_01_05" class="ost-tag-lo-apbio-ch09-s01-lo02 ost-tag-lo-apbio-ch09-s01-aplo-3-35"><media id="fs-id1778091" alt="This illustration shows the activation pathway for a heterotrimeric G-protein, which has three subunits: alpha beta, and gamma, all associated with the inside of the plasma membrane. When a signaling molecule binds to a G-protein-coupled receptor in the plasma membrane, a GDP molecule associated with the alpha subunit is exchanged for GTP. The alpha subunit dissociates from the beta and gamma subunits and triggers a cellular response. Hydrolysis of GTP to GDP terminates the signal.">
<figure id="fig-ch09_01_05" class="ost-tag-lo-apbio-ch09-s01-lo02 ost-tag-lo-apbio-ch09-s01-aplo-3-35"><media id="fs-id1778091" alt="This illustration shows the activation pathway for a heterotrimeric G-protein, which has three subunits: alpha, beta, and gamma, all associated with the inside of the plasma membrane. When a signaling molecule binds to a G-protein-coupled receptor in the plasma membrane, a GDP molecule associated with the alpha subunit is exchanged for GTP. The alpha subunit dissociates from the beta and gamma subunits and triggers a cellular response. Hydrolysis of GTP to GDP terminates the signal.">
<image mime-type="image/jpg" src="../../media/Figure_09_01_05.jpg" width="400"/>
</media>
<caption>Heterotrimeric G proteins have three subunits: <emphasis effect="italics">α</emphasis>, <emphasis effect="italics">β</emphasis>, and <emphasis effect="italics">γ</emphasis>. When a signaling molecule binds to a G-protein-coupled receptor in the plasma membrane, a GDP molecule associated with the <emphasis effect="italics">α</emphasis> subunit is exchanged for GTP. The <emphasis effect="italics">β</emphasis> and <emphasis effect="italics">γ</emphasis> subunits dissociate from the <emphasis effect="italics">α</emphasis> subunit, and a cellular response is triggered either by the <emphasis effect="italics">α</emphasis> subunit or the dissociated <emphasis effect="italics">βγ</emphasis> pair. Hydrolysis of GTP to GDP terminates the signal.</caption></figure><para id="fs-id2385574">G-protein-linked receptors have been extensively studied and much has been learned about their roles in maintaining health. Bacteria that are pathogenic to humans can release poisons that interrupt specific G-protein-linked receptor function, leading to illnesses such as pertussis, botulism, and cholera. In cholera (<link target-id="fig-ch09_01_06"/>), for example, the water-borne bacterium <emphasis effect="italics">Vibrio cholerae</emphasis> produces a toxin, choleragen, that binds to cells lining the small intestine. The toxin then enters these intestinal cells, where it modifies a G-protein that controls the opening of a chloride channel and causes it to remain continuously active, resulting in large losses of fluids from the body and potentially fatal dehydration as a result.</para>
Expand Down
2 changes: 1 addition & 1 deletion modules/m66378/index.cnxml
Original file line number Diff line number Diff line change
Expand Up @@ -63,7 +63,7 @@
closed until a signaling molecule (orange teardrop) binds to the channel protein. Then the channel protein changes conformation and allows ions (yellow
circles) to flow into (or out of) the cell. When the signaling molecule is released, the channel protein resumes its closed conformation, preventing ion flow.
Credit: Rao, A. and Fletcher, S. Department of Biology, Texas A&amp;M University.</caption></figure><para id="fs-id2592121"><term id="term-00019">G-protein-linked receptors</term> bind a ligand and activate a membrane protein called a G-protein. The activated G-protein then interacts with either an ion channel or an enzyme in the membrane (<link target-id="fig-ch09_01_05"/>). All G-protein-linked receptors have seven transmembrane domains, but each receptor has its own specific extracellular domain and G-protein-binding site.</para>
<para id="fs-id2336863">Cell signaling using G-protein-linked receptors occurs as a cyclic series of events. Before the ligand binds, the inactive G-protein can bind to a newly revealed site on the receptor specific for its binding. Once the G-protein binds to the receptor, the resulting change in shape activates the G-protein, which releases guanosine diphosphate (GDP) and picks up guanosine 3-phosphate (GTP). The subunits of the G-protein then split into the <emphasis effect="italics">α</emphasis> subunit and the <emphasis effect="italics">βγ</emphasis> subunit. One or both of these G-protein fragments may be able to activate other proteins as a result. After awhile, the GTP on the active <emphasis effect="italics">α</emphasis> subunit of the G-protein is hydrolyzed to GDP and the <emphasis effect="italics">βγ</emphasis> subunit is deactivated. The subunits reassociate to form the inactive G-protein and the cycle begins anew.</para><figure id="fig-ch09_01_05"><media id="fs-id1778091" alt="This illustration shows the activation pathway for a heterotrimeric G protein, which has three subunits: alpha beta, and gamma, all associated with the inside of the plasma membrane. When a signaling molecule binds to a G protein-coupled receptor in the plasma membrane, a G D P molecule associated with the alpha subunit is exchanged for G T P. The alpha subunit dissociates from the beta and gamma subunits and triggers a cellular response. Hydrolysis of G T P to G D P terminates the signal.">
<para id="fs-id2336863">Cell signaling using G-protein-linked receptors occurs as a cyclic series of events. Before the ligand binds, the inactive G-protein can bind to a newly revealed site on the receptor specific for its binding. Once the G-protein binds to the receptor, the resulting change in shape activates the G-protein, which releases guanosine diphosphate (GDP) and picks up guanosine 3-phosphate (GTP). The subunits of the G-protein then split into the <emphasis effect="italics">α</emphasis> subunit and the <emphasis effect="italics">βγ</emphasis> subunit. One or both of these G-protein fragments may be able to activate other proteins as a result. After awhile, the GTP on the active <emphasis effect="italics">α</emphasis> subunit of the G-protein is hydrolyzed to GDP and the <emphasis effect="italics">βγ</emphasis> subunit is deactivated. The subunits reassociate to form the inactive G-protein and the cycle begins anew.</para><figure id="fig-ch09_01_05"><media id="fs-id1778091" alt="This illustration shows the activation pathway for a heterotrimeric G protein, which has three subunits: alpha, beta, and gamma, all associated with the inside of the plasma membrane. When a signaling molecule binds to a G protein-coupled receptor in the plasma membrane, a G D P molecule associated with the alpha subunit is exchanged for G T P. The alpha subunit dissociates from the beta and gamma subunits and triggers a cellular response. Hydrolysis of G T P to G D P terminates the signal.">
<image mime-type="image/jpg" src="../../media/Figure_09_01_05.png" width="400"/>
</media>
<caption>Heterotrimeric G-proteins have three subunits: <emphasis effect="italics">α</emphasis>, <emphasis effect="italics">β</emphasis>, and <emphasis effect="italics">γ</emphasis>. When a signaling molecule binds to a G-protein-coupled receptor in the plasma membrane, a GDP molecule associated with the <emphasis effect="italics">α</emphasis> subunit is exchanged for GTP. The <emphasis effect="italics">β</emphasis> and <emphasis effect="italics">γ</emphasis> subunits dissociate from the <emphasis effect="italics">α</emphasis> subunit, and a cellular response is triggered either by the <emphasis effect="italics">α</emphasis> subunit or the dissociated <emphasis effect="italics">βγ</emphasis> pair. Hydrolysis of GTP to GDP terminates the signal.</caption></figure><para id="fs-id2385574">G-protein-linked receptors have been extensively studied and much has been learned about their roles in maintaining health. Bacteria that are pathogenic to humans can release poisons that interrupt specific G-protein-linked receptor function, leading to illnesses such as pertussis, botulism, and cholera. In cholera (<link target-id="fig-ch09_01_06"/>), for example, the water-borne bacterium <emphasis effect="italics">Vibrio cholerae</emphasis> produces a toxin, choleragen, that binds to cells lining the small intestine. The toxin then enters these intestinal cells, where it modifies a G-protein that controls the opening of a chloride channel and causes it to remain continuously active, resulting in large losses of fluids from the body and potentially fatal dehydration as a result.</para>
Expand Down

0 comments on commit e6f780b

Please sign in to comment.